The role of planetary health in urologic oncology

ABSTRACT

Introduction

Climate change and global warming are an omnipresent topic in our daily lives. Planetary health and oncology represent two critical domains within the broader spectrum of healthcare, each addressing distinct yet interconnected aspects of human well-being. We are encouraged to do our part in saving our planet. This should include the decisions we make in our professional life, especially in uro-oncology, as the healthcare sector significantly contributes to environmental pollution.

Areas covered

There are many aspects that can be addressed in the healthcare sector in general, as there are structural problems in terms of energy consumption, water waste, therapeutic techniques, transportation and drug manufacturing, as well as in uro-oncology specific areas. For example, the use of different surgical techniques, forms of anesthesia and the use of disposable or reusable instruments, each has a different impact on our environment. The literature search was carried out using PubMed, a medical database.

Expert opinion

We are used to making decisions based on the best outcome for patients without considering the impact that each decision can have on the environment. In the present article, we outline options and choices for a more climate-friendly approach in urologic oncology.

KEYWORDS:

• Environment
• planetary health
• human health
• sustainability
• uro-oncology
• carbon emissions
• carbon footprint
• global warming

1. Introduction

Climate change is a consequence of human activity and the resulting total amount of greenhouse gases produced [1]. The carbon footprint includes six greenhouse gases whose relative contribution to global warming varies [2]. In particular, these are carbon dioxide (CO₂), methane, nitrous oxide, hydrofluorocarbons, perfluorocarbons and sulfur hexafluoride [2]. The CO₂ footprint is usually expressed in tons of carbon dioxide equivalent (CO₂ equivalent, CO₂e) per year [2]. The impact of the climate change on human health is enormous [1]. It is estimated that air pollution is responsible for seven million deaths worldwide and for every fifth death globally [3,4]. Furthermore Gasparrini et al. formulated a model which predicts a 3–12.7% increase in heat related mortality at the end of the century [5].

Global warming has negative impacts on, for example, cancer incidence, respiratory disease, infectious diseases and reproductive function [1]. In turn, healthcare systems should develop strategies to slow global warming and counteract climate change [6]. To obtain these goals, there must be clarity about the extent to which climate change affects human health and what can be done to prevent it by adapting habits [1,7]. In uro-oncology, e.g. the selection of surgical treatments using endoscopic [8], laparoscopic and open surgical procedures [9] or aspects during the application of oncological therapies for urological cancers [10] are examples with transformative potential and opportunities.

This review describes the environmental aspect of contemporary established uro-oncological treatments and highlights possible options for reducing carbon emissions in the field of uro-oncology. The literature search was carried out using PubMed, a medical database. Special attention was paid to uro-oncology, healthcare system, human health, carbon footprint and environmental health/impact. The subsections appearing in the following were each placed in relation to these important key points.

2. General health care and environmental impact

2.1. Environmental impact on general health and preventive behavior

Global warming is an existential risk and is considered by the World Health Organization to be the greatest health problem of humanity [1]. It is already known that climate change leads to direct changes in nature with extreme weather conditions and resulting storms, floods, droughts or heat waves [11]. Indirect risks arise from changes in the biosphere, e.g. the burden of disease and the spread of disease vectors or the availability of food [11]. Above all, climate change and its environmental impacts have negative effects on e.g. cancer incidence, respiratory diseases, infectious disease patterns, and reproductive functions [1]. Physicians feel responsible to minimize these negative effects, prevent cancer and reduce its complications [3]. As the connection between cancer treatment and climate change is often underestimated, cancer care leaders, organizations, and cancer centers must now advocate for better education, research, and transformative action in this critical area [3]. These actions involve primarily energy choices, limiting the use of fossil fuels and promoting renewable energy sources [7,12]. It is important to consider that interventions should also aim to prevent disease and collectively mitigate climate change [7,12].

An important interface between diseases, including cancer, and climate change is air pollution [7]. Outdoor air pollution can be carcinogenic to humans, with a particular focus on fine particulate matter [7,13]. Air pollutants associated with fossil fuel combustion have other well-documented negative effects on human health in addition to cancer, e.g. cardiovascular and respiratory diseases [7]. Changes in transportation, particularly greater promotion of active modes of transport such as walking and cycling, can reduce air pollution while contributing to better health in several ways by increasing physical activity and therefore reduce the risk of obesity, diabetes, cancer and cardiovascular disease [7]. Air pollution has devastating consequences [3,4]. Particles not only cause local inflammation and oxidative stress, but also penetrate deep into the terminal bronchioles of the lungs and from there enter the circulation, where they cause systemic inflammation [3].

Furthermore, reducing meat consumption can help prevent a number of nontransferable and infectious diseases [7]. Processed meat has been classified by some institutions as carcinogenic to humans and red meat as probable carcinogenic [14]. In general, thermal food processing (e.g. frying, baking, grilling) in particular can release toxic carcinogenic substances such as acrylamide, furan and polycyclic aromatic hydrocarbons [15]. It is also known that processed foods contain substances that are intentionally used in food production, such as pesticides and additives [15]. Processed foods have a negative impact on the environment and public health. The risk of infectious diseases is also influenced by food production and supply choices [7]. The planetary footprint of meat consumption is huge, as it is already known that meat production is a large source of greenhouse gas emissions [7]. Agriculture is estimated to contribute at least 11–14%, or approximately 5.0–5.8 gigatons of CO₂e per year, to total anthropogenic greenhouse gas emissions, of which approximately 75% comes from livestock farming [7,16].

2.2. Optimization of energy efficiency in hospitals

In general, global healthcare is the fifth largest carbon emitter on the planet [3,17]. These emissions are typically divided into three parts (Figure 1) [3]. Direct emissions from healthcare facilities and healthcare vehicles account for approximately 17% of this sectors’ global footprint [3]. Another 12% are attributed to indirect emissions from purchased energy sources such as electricity, cooling and heating [3]. The main source of emissions, 71%, is determined by the healthcare supply chain, through the production, transportation and disposal of goods and services such as pharmaceuticals and other chemicals, food and agricultural products, medical devices, hospital equipment and instruments [3].

Figure 1. CO₂–emissions of healthcare sector divided into the major contributive factors [3].

CO₂ = carbon dioxide.

In order to reduce energy consumption in hospitals, it is important to modernize buildings [18,19]. Optimizing the use of buildings with on-site energy production can lead to a significant reduction in hospital emissions [18,19]. Clean energy sources generated on-site can improve the resilience of healthcare facilities to power outages, which are becoming more frequent as a result of climate change [20–22]. Furthermore, pollution in surrounding neighborhoods can be reduced by energy generation on-site [20–22]. Another way to improve the carbon footprint of hospitals is to carry out energy audits and optimize energy efficiency and energy use, particularly for ventilation or laundry, reduce food waste and publish carbon footprints [1]. In cancer prevention and treatment, more targeted screening programs, collection and sustainable use of anesthetic gas in the operating room, waste minimization in the manufacture and administration of systemic therapeutics as well as more efficient medical devices can improve the use of available resources and reduce emissions [18,19]. Furthermore it is also necessary to switch to renewable energies [23]. Ureterorenoscopy, which is frequently used in stone disease and uro-oncology, is a good example. If a conventional energy mix is used in a hospital, the impact on public health is 4.32 kg CO₂e per year for reusable flexible ureteroscopes compared to 6.25 kg CO₂e per year for disposable flexible ureteroscopes [23]. This value is lower for both types of ureteroscopes when using renewable energy [8,23].

Using a model like the one proposed by MacNeill and colleagues can help accelerate the creation of climate-smart infrastructure to reduce emissions [1,24]. This model envisages reducing demand, providing appropriate care and operating sustainably [1,24].

One study reported that a magnetic resonance imaging scan is equivalently wasteful to driving a car for 90 miles (145 kilometers (km)), a computed tomography scan is equivalent to traveling 45 miles (72 km), and plain X-rays are equivalent to driving 6 miles (10 km) [1,25] (Figure 2). By consequence, imaging performed at an inappropriate frequency will not only harm the individual in terms of radiation exposure but is also wasteful and damaging to the climate [1,25].

Figure 2. Carbon dioxide (CO₂) footprint of diagnostic imaging compared to the CO₂ footprint of driving a car in kilometers (km) [1,25].

MRI = Magnetic resonance imaging; CT = Computed tomography.

In this regard, it is also considerable that blood tests are only taken when they are necessary [1,26]. Each blood test corresponds to a consumption of 49–116 g CO₂ per examination [1,26]. With hundreds of millions of blood tests performed annually, the cumulative effect is significant [1,26]. By establishing and adhering to guidelines, improvements could be achieved without affecting daily workflow or patient health [1,26].

Finally, healthcare institutions purchase large quantities of food on a daily basis [27]. These institutions can also contribute to solutions by striving for environmentally friendly aliment choices [27]. Hospital foodservices have the potential to make a positive and sustainable contribution to local food systems and planetary health [27].

3. Relationship between environmental factors and uro-oncology

3.1. Influence of environmental factors due to global warming on uro-oncological disease

3.1.1. Bladder cancer

Bladder cancer is a common uro-oncological disease that is associated with significant morbidity, mortality and costs. The main risk factors for bladder cancer are environmental or occupational exposure to carcinogens, particularly tobacco use [28]. Tobacco use in general is responsible for about one third of cancer deaths worldwide, and also has a significant ecological footprint [7,29]. Greenhouse gas emissions from purchased goods and services, transport and distribution of tobacco accounted for 3,611,000 tons [30]. The sum of these emissions, just for one manufacturer and one year, is more than 4.5 million tons [7,30]. Tobacco production is also extremely water-intensive, at least 23,247,000 cubic meters per year [7]. The risk of developing bladder cancer is significantly reduced by quitting smoking [31]. In addition to primary prevention, quitting smoking is crucial to prevent recurrences [31]. This not only reduces the carbon footprint, but also protects human health. A specific scenario is the increased occurrence of bladder cancer in arsenic-contaminated regions [32]. A large number of epidemiological studies have examined the relationship between environmental factors and the occurrence of carcinoma of the urinary tract. Besides cigarette smoking and mostly occupational exposure to aromatic amines in the chemical industry, exposure to arsenic-contaminated drinking water (>300 micrograms per liter (μg/l)) is the major environmental risk factor for urothelial carcinoma [33]. In addition, arsenic contamination can also be detected to some extent in food, tobacco production and breathing air [33]. Due to global warming, the arsenic content in drinking water and food will increase significantly [34]. Contamination of groundwater with geogenic arsenic poses a major health risk to millions of people [35]. Long-term exposure to arsenic can affect human health and is considered one of the most common environmental causes of cancer [35]. There is little information about exposure to arsenic in drinking water and demographic and clinicopathological characteristics of patients with bladder cancer living in arsenic-exposed regions [32]. Bladder cancer due to arsenic contamination appears to harbour different biology. Arsenic exposure was identified as an independent predictor of aggressive tumor phenotypes in bladder cancer [32]. Worldwide, arsenic contamination relevant to the ecosystem has been recorded, especially in developing and newly industrialized countries, due to the steadily increasing environmental pollution caused by the copper and heavy metal industry [36]. In the meantime, this contamination has also been scientifically documented over a long term course [36]. A Chinese working group, for example, reported a 13.9-fold and 21.4-fold increase in arsenic exposure in two contaminated lakes within a period of 50 years, which was accompanied by the loss of zooplankton and an increase in heavy metal-tolerant algae strains [36]. A regionally increased incidence of urothelial carcinoma in the vicinity of industrial areas has also been epidemiologically described in Western countries [32]. Analogous to the environmental medicine and health policy approaches required to control arsenic exposure and contamination in high-risk areas, the need for adapted urological screening programs for early tumor detection in these regions must also be discussed [32]. It has also been shown that bladder cancer patients within contaminated areas show a significantly worse survival [37]. Furthermore, grain yields could decrease by 39% in the future compared to yields at current arsenic soil concentrations [34]. Future climatic conditions and global warming will lead to a nearly two-fold increase in inorganic arsenic concentrations in grains [34]. The increase of arsenic soil contamination caused by climate change and the according plant response will lead to unforeseen losses in rice grain productivity and quality and finally increase in arsenic-induced carcinoma [34,35].

Infections with the parasite schistosoma haematobium are also a known risk factor of squamous cell carcinoma of the urinary bladder. In the affected areas in the Middle East and parts of Africa, bladder carcinoma is the most common type of cancer [38,39]. The natural intermediate hosts of the disease are freshwater snails that excrete cercariae. Through skin contact with cercariae, the parasite penetrates the skin and enters the bloodstream [38,39]. The eggs migrate via the bloodstream to the walls of the bladder and ureter, where they cause a granulomatous inflammation. If the inflammation persists for a long time, fibrosis with calcifications and squamous cell carcinoma of the bladder can develop [38,39]. In certain regions around Lake Malawi, a significant increase in schistosome infections has been observed since the 1980s [40,41]. Madsen et al. hypothesized that overfishing and the resulting decline of predators in parts of Africa has led to a sharp increase in freshwater snails, which serve as intermediate hosts for the schistosomiasis pathogen and thus contribute to the increasing incidence of the disease in the region [42]. A recent systematic review by Hoover et al. highlights the potential impact of agrochemical pollution on the transmission of schistosomiasis [43]. With increasing agricultural use and the associated use of agrochemicals, the transmission of schistosomiasis threatens to increase, which could jeopardize ongoing efforts to combat and eradicate the disease in endemic areas [43]. Global warming itself could also increase the area in which the host and parasite can survive, and thus the regions in which the disease can be transmitted [44].

3.1.2. Prostate cancer

Prostate cancer is known to be a hormone-dependent malignancy that can be effectively treated by interfering with androgen availability or androgen signaling pathways [45]. In this context, it is likely that hormonally active substances such as endocrine disrupting chemicals (EDC) may play a role in pathogenesis [45,46]. EDC are defined as ‘an exogenous substance or mixture that alters function(s) of the endocrine system and consequently causes adverse health effects in an intact organism, or its progeny, or (sub)populations’ [46]. Several groups of EDC, e.g. bisphenols, phthalates, phytoestrogens and mycoestrogens, have been investigated for their role in the development of prostate cancer [47]. These molecules are able to influence the androgen and estrogen signaling pathways, either directly by binding to receptors or indirectly by influencing steroidogenesis, the expression of sex steroid receptors via epigenetics or the activation mechanisms of nuclear receptors [47]. As such, they can significantly influence the development of prostate cancer and its progression [47]. However, many of these chemicals have multiple cellular targets depending on their concentration [47].

It is also important to understand that different therapeutic approaches may produce different carbon emissions [1,48]. The example of prostate cancer clearly shows that invasive CO₂-intensive treatment is not always necessary [49,50]. With a median follow-up of 15 years, studies have found that mortality from prostate cancer detected due to rising PSA levels remained very low regardless of whether men were assigned to active surveillance, prostatectomy, or radiation therapy [49]. Radical surgical or radiotherapeutic treatment resulted in a lower risk of disease progression than active surveillance but did not reduce prostate cancer mortality [49]. Men with newly diagnosed, localized prostate cancer and their physicians can take the time to carefully consider the trade-offs between harm and benefit of treatments and then decide whether to use invasive or noninvasive therapy [49]. The PIVOT study also demonstrated that after nearly 20 years of follow-up in men with localized prostate cancer, surgical treatment was not associated with significantly lower prostate cancer mortality than active surveillance [50]. Surgery was correlated with a higher incidence of adverse events [50]. However, treatment due to disease progression was less common after radical therapy [50]. As a future perspective, decision making on therapeutic strategies in PC might be made integrating the expected carbon emissions. However, any impairment of patient care should be avoided.

3.1.3. Penile cancer

Many risk factors for penile cancer have already been identified, including phimosis, balanitis, obesity, lichen sclerosus, smoking, and psoral UV-A (ultraviolet A) phototherapy [51]. Additionally, human papillomavirus (HPV) has been linked to nearly 40% of penile cancer cases [51]. It is considered as one of the most common sexually transmitted diseases in the United States [52]. HPV is associated with several types of cancer in men, including oral, anal and penile cancer [52]. Currently, public health campaigns aim to raise awareness, promote better hygiene and use HPV vaccines [51]. However, it is interesting that environmental influences caused by global warming also appear to be linked to the development of high-risk penile cancer [52]. As mentioned above, humans are exposed to arsenic through water, food and air in particular regions. Contaminated drinking water is a leading cause of arsenic toxicity worldwide [34,35]. Inorganic arsenic is an environmental pollutant with immunosuppressive properties [52]. Niemann et al. found that arsenic acid is associated with high-risk HPV infections in men and thus an increased risk of penile cancer [52].

3.1.4. Renal cell carcinoma

The higher risk for smokers to develop Renal cell carcinoma (RCC) is well described [53,54]. But there is also a significantly higher risk to people which are passive smokers [53,54]. Therefore, smoking can be recognized as an environmental risk factor [53,54]. A passive exposure over more than 20 years can increase the risk for RCC 2–4 times [53]. Similar to bladder cancer and penile cancer there seems to be a connection between arsenic exposure and the mortality rates of kidney cancer [55,56]. A systematic review showed a correlation between an elevated incidence of renal cell carcinoma and high arsenic concentration in the drinking water [56]. Exposure to heavy metals like cadmium and lead also show a significantly higher risk for developing RCC [57,58]. The sources of lead exposure greatly vary in different geographical regions and dependig on the economic and industrial status of states and countries [59].

As of yet, there are no known associations between changing environmental factors due to global warming and testicular cancer.

3.2. Carbon footprint of surgical therapy in uro-oncology

Surgical therapy is a cornerstone in the management of localized disease in uro-oncology. Two systematic reviews concerning the carbon footprint of surgical procedures found that the most important factors are energy consumption, anesthesia and disposable surgical equipment [60–62]. In addition, perioperative services have a large carbon footprint, such as the energy used for ventilation and the use of anesthetic gas [1,63,64]. There are numerous opportunities to establish sustainability in the perioperative environment. These include for example standardizing instrument trays, switching from disposable tools to reusable instruments (such as gowns, drapes, trocars, and equipment), or reducing material waste [1].

Heating, ventilation and air conditioning account for the majority (90–99%) of operating room energy consumption [62,65]. This can be reduced through operating room design, the installation of occupancy sensors or after-hours setback systems, reduced airflow turnover, the development of newer buildings with improved energy efficiency, as well as the use of renewable energy sources [62,65]. Newly introduced infection prevention measures in the operating room, such as the use of air purification systems, may unfortunately often lead to significant greenhouse gas emissions [66]. It has also been shown that they do not necessarily reduce the risk of infection in the operating room [66].

Another important factor that contributes to the carbon footprint is surgical equipment [60–62]. In the diagnosis of urothelial carcinoma of the upper urinary tract, follow-up studies of the ureter and renal pelvis must be performed regularly by ureteroscopy. The cost-effectiveness of reusable flexible ureteroscopes is assessed on the basis of acquisition, repair and service costs as well as cleaning, disinfection costs, sterilization costs and costs for healthcare and time [67]. Flexible single-use ureteroscopes, on the other hand, incur acquisition and storage costs for the devices themselves and the corresponding work stations, as well as costs for waste disposal [67]. Ureteroscopes are semi-critical devices due to their contact with the patients’ mucous membranes and must be sterilized with highly effective disinfectants [67,68]. Failure to properly disinfect endoscopes may lead to the transmission of infections [67,68]. The use of a disposable ureteroscope also overcomes the problems caused by reusable ureteroscopes, e.g. repair and service costs, cleaning, disinfection and sterilization costs [67]. However, the optical and technical characteristics of the reusable digital ureteroscopes were more favorable compared to the disposable devices; specifically, the reusable endoscope showed higher light emission and performed best in all subjective image quality categories assessed [69]. Despite similar bending ability and flow rates, intrapelvic pressure during the surgical procedure was higher with reusable devices [34]. A medico-economic study showed that despite the high costs of reprocessing and repair of reusable flexible ureteroscopes, they are more cost-effective than single-use flexible ureteroscopes for centers with a high volume of ureteroscopic activities [70]. However, for centers with a low volume of flexible ureteroscopic procedures, single-use flexible ureteroscopes may be more cost-effective [70]. Urologists should be aware that the typical life cycle of urological instruments is a significant source of environmental emissions [8]. The total carbon footprint of the life cycle of a reusable ureteroscope was calculated to be 4.47 kg of CO₂ per case, and the manufacturing cost of the ureteroscope per case was 0.06 kg of CO₂ [8]. The total carbon footprint of the life cycle assessment of a single-use ureteroscope was 4.43 kg of CO₂ and the carbon footprint of the production was 3.45 kg of CO₂ per scope and endourological case [8] (Table 1). More recent data show that overall results for disposable flexible ureteroscopes were comparable at 4.93 kg CO₂e [8,23]. However, the overall results for reusable flexible ureteroscopes were significantly lower at 1.24 kg CO₂e [23]. The increased overall estimate for reusable flexible ureteroscopes in other publications is probably almost exclusively due to the estimate of a high burden from reprocessing of 3.95 kg CO₂e [8,23]. The total carbon footprint of the life cycle between reusable and disposable ureteroscopes therefore hardly differs [8,23]. However, the footprint for the production of disposable ureteroscopes is significantly larger [8]. In another study on this topic, Kemble et al. found differences between flexible disposable and reusable cystoscopes [71]. Taking into account the production, waste and reprocessing of reusable devices, the carbon footprint shows a significant difference between disposable and reusable cystoscopes with 2.4 kg CO₂ versus 0.53 kg CO₂ per use [71] (Table 2). Finally, reusable surgical products are also more resistant to shocks and disruptions in the supply chain, which are becoming increasingly common with climate change [22,72].

Table 1. Carbon footprint of reusable and single-use ureteroscopes in kilogram of carbon dioxide (kg CO₂) per case [8,70].

	Reusable ureteroscope [8,70]	Single-use ureteroscope [8,70]
Life cycle (per case)	4.47 kg CO2	4.43 kg CO2
Manufacturing (per case)	0.06 kg CO2	3.45 kg CO2

Table 2. Carbon footprint of reusable and single-use cystoscopes in kilogram of carbon dioxide (kg CO₂) per case or in kilogram (kg) per kg device for manufacturing [71].

	Reusable cystoscope [71]	Single-use cystoscope [71]
Manufacturing	11.49 kg CO2/kg device	8.54 kg CO2/kg device
Per case	0.53 kg CO2	2.4 kg CO2

Aspects of environmental interest were previously also discussed in open versus laparoscopic surgery for prostate cancer, muscle-invasive bladder cancer and kidney tumors [73]. Laparoscopic and robotic surgical techniques and indications have expanded dramatically over the last 30 years since the introduction of laparoscopy [74]. In urology, for example, the majority of radical prostatectomies in the United States are currently performed with robotic surgery [74]. The CO₂ emissions of minimally invasive surgery in the United States have a significant environmental impact [74]. In 2012, the total CO₂ emissions during the minimally invasive surgery were 303 tons/per year [74]. The subtotal of CO₂ emissions for industrial gas production, electricity generation and supply, as well as gas production was calculated at 351,400 tons/year [74].]. Finally, the incineration of 208,441 kg of biomedical plastic waste from the use of disposable trocars and robotic instruments caused 1,251 tons of CO₂ emissions and total indirect CO₂ emissions of 355,621 tons [74].

Woods et al. showed that the three surgical modalities (open surgery, laparoscopic and robot-assisted minimally invasive surgery) were comparable in terms of their relative contribution of energy consumed to the total carbon footprint, with the energy consumption of robot-assisted laparoscopic surgery accounting for 61% of the total carbon footprint of each procedure, that of laparoscopic surgery for 61.5% and that of open surgery for 63.4% [9]. However, the absolute energy consumption differs significantly between the different approaches [9]. The total carbon footprint of a robot-assisted minimally invasive procedure is 40.3 kg CO₂e/patient [9]. This corresponds to an increase of 38% compared to laparoscopic surgery (29.2 kg CO₂e/patient; p < 0.01) and an increase of 77% compared to laparotomy (22.7 kg CO₂e/patient; p < 0.01) [9]. Open surgery produced the lowest amount of solid waste at 8.3 kg CO₂e/patient compared to robot-assisted minimally invasive surgery (14.3 kg CO₂e/patient) and laparoscopy (11.24 kg CO₂e/patient) [9] (Figure 3, Table 3).

Figure 3. Total carbon footprint of robot-assisted minimally invasive surgery, laparoscopic surgery and laparotomy in kilogram carbon dioxide equivalent (kg CO₂e) per patient [9].

Table 3. Carbon footprint compared between surgical approaches in kilogram carbon dioxide equivalent (kg CO₂e) [9].

	Total carbon footprint in kg CO2e/patient [9]	Solid waste In kg CO2e/patient [9]
Robot-assisted minimally invasive surgery	40.3	14.3
Laparoscopic surgery	29.2	11.24
Open surgery	22.7	8.3

Laparoscopic and robot-assisted minimally invasive surgery have many advantages [75]. e.g. large open wounds or cuts can be avoided, thereby reducing blood loss, pain and discomfort [75]. Additionally, a smaller amount of analgesia is required and the fine instruments cause less tissue injury [75]. The rate of postoperative complications is generally lower, particularly those related to the wound such as dehiscence, infection and incisional hernias [75]. Due to the disadvantages listed above, open surgery should be indicated less frequently nowadays [75]. However, the impact on the environment and the higher carbon footprint of minimally invasive operations must be taken into account and demands further efforts and research to make minimal-invasive, especially robotic surgery, more climate efficient [9,74].

Desflurane is an inhaled anesthetic gas with 2,500 times the global warming potential of CO₂ [76]. Calculations showed very high work-related emissions for anesthesiologists totaling 17.1 tons CO₂e per person per year. By reducing the use of desflurane, these emissions could be reduced to 5.4 tons CO₂e per person per year [76]. Emissions per case can decrease from 38 to 12 kg CO₂e [76]. As long as efficient scavenging systems are not available, the use of desflurane should be questioned or omitted for ecological reasons [76]. The environmental impact of general anesthesia can be reduced by using low global warming potential inhalational agents, gas evacuation systems and preferring regional or total intravenous anesthesia [62,77].

3.3. Carbon footprint of radiation therapy in uro-oncology

Radiation therapy plays a crucial role in the multidisciplinary treatment of urological cancers [78]. Radiation therapy has a wide range of applications, ranging from treatment with curative intent to alleviation of symptoms of an incurable urological disease [78].

The CO₂ footprint of radiation therapy in uro-oncology is interesting in prostate cancer, where local radiotherapy represents an alternative to radical curative surgical therapy [49]. In one study, 10 patients each received conventional fractionated therapy for prostate cancer (28 fractions) and 10 patients each received stereotactic body radiation therapy of the prostate (SBRT) (5 fractions) [79]. On average, the lowest carbon emissions per course were measured for prostate SBRT (2.18 kg CO₂; interquartile range 1.92–2.30) and the highest carbon emissions for conventional prostate cancer treatment (17.34 kg CO₂; interquartile range 10.26–23.79) [79]. This corresponds to the CO₂ equivalent emissions of an average journey of 5.4 miles (8.7 km) or 41.2 miles (66.3 km) in a standard vehicle [79]. In ‘standby’ mode, a conventional radiation device consumes between 64.8 kilowatt hours (kWh) and 112.0 kWh of electricity per day [79].

In direct comparison to surgical therapy, radiotherapy appears to produce fewer carbon emissions, considering that robot-assisted surgery consumes 40.3 kg CO₂e/patient, laparoscopic surgery 29.2 kg CO₂e/patient and an open surgery 22.7 kg CO₂e/patient [9,79]. In addition, significantly smaller amounts of waste are produced during radiation therapy [9,79] (Table 4). In the study, however, the energy consumption and CO2 footprint due to transportation for frequent outpatient appointments was not taken into account, which can greatly vary depending on the regional medical supply structures [79].

Table 4. Carbon footprint of surgical treatment versus radiation therapy in kilogram carbon dioxide equivalent (kg CO₂e) per patient in the literature [9,79].

Surgical treatment [9]		Radiation therapy [79]
Robot-assisted minimally invasive procedure	40.3 kg CO2e/patient	Conventional radiation therapy	17.34 kg CO2e/patient
Laparoscopic surgery	29.2 kg CO2e/patient	Prostate SBRT	2.18 kg CO2e/patient
Open surgery	22.7 kg CO2e/patient

SBRT = stereotactic body radiation therapy.

4. Reducing carbon emissions in drug therapies

Anticancer therapy by using antiproliferative drugs plays an important role in the treatment of advanced and metastatic uro-oncological diseases [10]. The treatment of malignant diseases of the genitourinary system has developed rapidly in recent years, with new treatment options and novel compounds for renal cell carcinoma, urothelial carcinoma, and prostate carcinoma [10]. Currently, systemic therapies include not only chemotherapy, but also immunotherapy or therapy with novel targeted substances [10]. Approaches to reduce carbon emissions in this sector include local manufacturing of drugs and care for patients close to home, as well as telemedicine [80–82].

Due to the high energy costs of drug manufacturing and drug research coupled with the high transportation costs of drug distribution, upstream pharmaceutical carbon emissions are generally significant [83]. For example, in the United Kingdom of Great Britain and Northern Ireland, health and care services are responsible for around 5% of total carbon emissions and most of this comes from the supply chain, the transport of drugs and the equipment used to produce drugs [84]. Wastewater from drug production has been shown to have harmful effects on wildlife and contribute to antimicrobial resistance [84]. In the National Health System, 30% of carbon emissions are caused by the manufacture and supply of pharmaceuticals and medical devices; patients’ travel account for 5% [18]. Local production of drugs plays a critical role in maintaining the resilience of national health systems, particularly in facilitating access to needed medicines and reducing exposure to imports and international supply chains [81]. But of course, local production of pharmaceuticals shortens transport routes and reduces carbon emissions [83].

Furthermore, the introduction of virtual consultations and meetings during the Coronavirus disease of 2019 (COVID-19) pandemic has demonstrated solutions to avoid travel for patients and staff [18,19]. By expanding necessary structures and refraining from active travel, transport emissions are further reduced, which can lead to health benefits [18,19]. The use of telemedicine services leads to a reduction of the carbon footprint of healthcare [80]. There is a close connection between the reduction of the carbon footprint and the average travel distance savings [80] and a large part of the savings in emissions can be attributed to the reduction in travel to appointments [80]. The implication of virtual consultation may also have clinical advantages through a more stable cycle of consultations and an easy connection between patient and physician [85] as well as financial benefits [86,87]. In order to reduce the carbon footprint of healthcare, a radical reform of healthcare delivery pathways is therefore required [82]. Only patients whose healthcare cannot be guaranteed close to their place of residence should be admitted to hospitals [82]. For example, reducing avoidable hospital admissions and shortening length of inpatient stay can save both money and carbon emissions [82]. It is estimated that 60% of current hospital inpatients actually do not require hospitalization [82].

5. Climate change task forces and health programs

Climate change task forces have been integrated recently in the healthcare system [3]. These societies include as members top cancer organizations, like the American Society of Clinical Oncology (ASCO) [3]. Some of these task forces have created or are currently developing policy statements outlining how climate change will affect their patients and calling for action [3]. Physicians are considered trustworthy and well positioned to talk to patients and healthcare companies about climate change [6]. A unified strategy for medical societies is essential to effectively reduce their carbon footprint and address health concerns [6]. Medicine is delineated to play a key role in efforts to mitigate and adapt to climate change [6]. Although some organizations are already committed and active in the transformative process against climate change, most need to quickly improve their efforts [6].

Childhood and adolescent cancer survivors represent a high-risk group for chronic noncommunicable diseases and the development of secondary cancers [88]. An environmental and community health program has been established in the Spanish region of Murcia for the long-term follow-up of these patients [88]. It has already been proven that cancer survivors who lived in areas with very poor outdoor air quality had lower survival rates [88]. Urban air pollution increases the risk of cardiovascular and respiratory infections, which could contribute to increased mortality in patients with vulnerable immune systems [88,89]. Therefore, reducing urban air pollution could help improve the well-being and survival chances of cancer survivors [88]. It is very important to widely establish environmental and community health programs because ultimately, monitoring individual carbon footprints and creating a healthier lifestyle and environment for cancer survivors could promote well-being, environmental awareness and empowerment [88].

As of today, the carbon footprint is not a relevant factor in any medical or oncological guidelines. This may not only be due to the fact that there is a lack of awareness, but also limitations of scientific evidence within the field of planetary health and medicine. With more intensified research in this particular field of medicine, more condensed international research programs and funding, this must be overcome rapidly. By consequence, it will be important that future oncology guidelines reflect holistic approaches to environmental protection and the reduction of carbon emissions in their recommendations. Environmental protection and planetary health should become a subject of clinical studies and the guideline culture.

6. Recommendations for healthcare professionals and cancer patients to reduce the carbon footprint

According to the above-mentioned information we provide some recommendations for healthcare professionals and cancer patients to reduce the carbon footprint in daily life, wherever acceptable and plausible (Table 5). Not only healthcare professionals, but also cancer patients themselves can contribute to reduce environmental pollution.

Table 5. Recommendations for healthcare professionals and cancer patients to choose environmentally friendly options for action [1,3,7,8,18–20,25–27,29,49,50,70–72,80–82].

Recommendations for healthcare professionals	Recommendations for cancer patients	Recommendations for both
Avoid unnecessary blood tests [1,26]	Consider active modes of transport by increasing physical activity [7]	Consider environmentally friendly food choices [7,27]
Avoid unnecessary imaging [1,25]	Reduce tobacco use [7,29]	Consider telemedicine/virtual consultations [80]
Shortening length of inpatient stay [82]	Consider care for patients close to home [80–82]
Using reusable and energy-efficient surgical devices [8,70–72]
Consider active surveillance concepts/conservative procedures [49,50]
Review local manufacturing of drugs [81]
Reduce general waste and water consumption [18,19]
Participate in climate change task forces [3]
Increase use of renewable energy that is generated on-site [18–20]

7. Conclusion

Climate change and global warming are an omnipresent issue in our daily lives. As shown above, there are many approaches within the healthcare system, and especially in uro-oncology, to accomplish an improved perception and transformative action towards more sustainable healthcare. In uro-oncology, patients are often faced with life-threatening diseases that require maximum efforts by our healthcare systems to achieve cure and palliation. Nevertheless, changes and adaptations in multiple sectors of uro-oncology appear feasible without compromising the quality of care.

8. Expert opinion

Implementing research on planetary health aspects within uro-oncology could affect guidelines on which daily clinical decisions are based on. In general, oncology should not be a field excluded from critical view.

Healthcare fundamentally focuses on optimizing patients outcomes and improving healthcare costs while streamlining care delivery [1]. Treatment decision making is based on the result of clinical trials and quality of data. Minimal-invasive surgical techniques show a better outcome for our patients, and have substantially increased in recent years, with still growing numbers and broader indications for minimally invasive and robotic surgeries to be expected throughout the near future [74,75]. While these forms of therapy achieve a consistently better outcome for the patient, robotic surgery in particular appears disadvantageous referring to the impact on planetary health [9].

Similar questions and scenarios can be outlined for other scenarios in uro-oncology, e.g. regarding the amount and frequency of blood tests [1,76] and imaging [1,25]. It remains challenging, however worthwhile, to extend research , e.g. with life-cycle-assessment analyses for different (equally effective) therapies, in oncology. This situation is of growing interest given the plethora of new treatment options and newly approved drugs and regimens in uro-oncology. Noteworthy, the environmental impact can be different in different hospitals and countries, or depending on where and how the substances are produced, transported and stored. Data on energy consumption, water waste and carbon footprint are often limited and difficult to obtain and can therefore not contribute to an informed decision to date.

Nevertheless, planetary health research will be offer an important new focus, integrating life-cycle analysis of procedures can help to elucidate options to improve the carbon footprint in uro-oncology and aid in more planetary health based decision making. In addition, structural changes in hospitals and practices, starting with the use of reusable energy, will be of immediate environmental value. We should also rely more on telemedicine and conduct fewer face-to-face consultations. There are many subtle changes, for example using more sustainable materials, diffrerentiated use of single-use instruments and optimized ways to sterilize equipment that are at hand even now. Overall, more education and information for all health care providers and participants is needed. Therefore, academic hospitals and universities should be obliged to integrate planetary health into their curricula.

Article highlights

• The environmental impact on health is enormous. Preventive behavior to improve human health and the health of the planet is of existential and vital importance.

• Energy efficiency must be optimized in many areas of the healthcare system, especially in surgical treatment, drug therapy and the design of hospitals.

• Expected carbon emissions could be incorporated into decision making on treatment decisions. However, any impairment of patient care should be avoided.

• Climate change task forces should be established to delay climate change in healthcare in general and also in the complex multidisciplinary field of uro-oncology.

Declaration of interest

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This paper was not funded.