Update on melanoma and non-melanoma skin cancer

Abstract

In this article, we will summarize some of the highlights of the third annual conference on skin cancer, with special emphasis on the the recent advances regarding melanoma and non-melanoma skin cancer epidemiology, diagnosis and treatment. Topics were particularly addressed to a newly developing medical branch in Australia, namely that of Primary Care Skin Cancer Practitioners, and focused on strategies to improve primary and secondary prevention and early detection of melanoma and non-melanoma skin cancer using dermoscopy. Controversies related to skin cancer screening programs and recent progresses for treating advanced melanoma were additionally discussed. Yet, besides its scientific goals, the conference aimed also to encourage research originating in primary care and relevant to primary care.

Keywords::

• actinic keratosis
• dermoscopy
• epidemiology
• melanoma
• nevi
• non-melanoma skin cancer

The School of Medicine at the University of Queensland (QLD, Australia), together with its partner HealthCert, organized this third annual conference on skin cancer, which took place at Hamilton Island on 5–6 August 2011. Its goal was to provide a venue for updating primary-care practitioners with special interest in diagnosing and treating skin cancer, on recent research in melanoma and keratinocyte cancers, as well as to exchange professional information and network with others working in the field of skin cancer. The fact that more than 200 primary care practitioners attended this meeting points toward a newly developing medical branch in Australia, namely that of Primary Care Skin Cancer Practitioners.

Topics encompassed several aspects related to melanoma and keratinocyte cancers including pathogenesis, primary and secondary prevention, early diagnosis and current progress in treating skin cancer. A group of national and international leaders in the field of skin cancer ran practical pre- and post-conference workshops and a series of plenary presentations; a key feature of the conference were debates, discussions, and moderated questions from the audience. Here, we have summarized some of the highlights of this conference.

Pathways of melanoma

David Whiteman pointed out that cutaneous melanoma arises through the interplay of both environmental and genetic factors. With respect to host factors, the role of nevi was reviewed, both as ‘precursors’ and as risk markers for melanoma. Emerging evidence from several disciplines suggests that a person’s propensity to develop nevi is genetically determined, with expression also influenced by environment. Some people have a propensity to develop many nevi, whereas others have little propensity to develop nevi. With this regard, he presented the ‘divergent pathway hypothesis for melanoma’, which posits that this characteristic (nevus propensity) underscores the two main pathways to melanoma development [1]. Among those with low propensity to develop nevi, repeated and cumulative exposure to the sun is required for melanoma development. By contrast, in people with high nevus propensity, only modest amounts of sun exposure are required to develop melanoma, and this exposure is probably most harmful early in life. Findings from recent genome-wide association studies of melanoma were integrated with previous research from epidemiological and molecular studies, each of which contributed new understanding to the ‘divergent pathway’ hypothesis for melanoma [2].

New insights into nevogenesis

Iris Zalaudek presented that nevi in children differ significantly from nevi in adults with respect to their epidemiology, morphology, dynamic, genetics and associated melanoma risk. Zalaudek explained these differences by a new concept of nevogenesis, which postulates that nevi may be derived from melanocytes at different maturation stages in different levels of the skin [3,4].

Screening for melanoma

A hot topic of this conference focused on melanoma screening and the early detection of melanoma.

Whiteman reviewed the available evidence for melanoma screening and concluded that a key challenge for all screening programs is the low positive-predictive value of the skin examination [5]. This means that most of the people who return a ‘positive test’ do not have or will not die from melanoma, a situation which introduces harm and costs that weigh against potential benefits. The presentation concluded with a commentary on primary care skin cancer screening in Australia (‘case finding’), and a review of the national skin cancer screening program in Germany.

Giuseppe Argenziano presented the preliminary data of a survey, which showed that the number needed to excise (NNE) decreased significantly over a 10-year period in specialized clinics (from 12.8 to 6.8), whereas it remained essentially unchanged, at approximately 29, in nonspecialized clinics. Thereby, most of the effect on the improved NNE was due to an increase of excised melanomas and a decreasing proportion of excised nevi; it was also shown that the highest NNE rates were seen in young individuals with high nevus counts. Based on this, it was concluded that much of the economic burden of melanoma screening results from excisions of nevi, especially in young patients.

Strategies to improve melanoma detection

Various strategies to optimize melanoma screening have been discussed. Among those, the implementation of dermoscopy on almost all clinically unselected lesions using a comparative approach and digital dermoscopic monitoring were advocated.

Scott Menzies from the Sydney Melanoma Diagnostic Center (NSW, Australia) presented an extensive review on the impact of digital monitoring in the management of patients with multiple nevi and concluded that this method is safe and improves the early detection of featureless melanomas and decreases the number of excisions of nevi [6,7].

Special attention has been paid on the role of opportunistic screening in the detection of melanoma. Argenziano presented the data of a prospective multicenter study, in which opportunistic skin cancer screening in a population of patients who were not scheduled to receive a total body skin examination revealed one out of 47 patients having any type of skin cancer [8]. Factors that significantly increased the likelihood of finding a skin cancer by total body skin examination were older age, patients consulting for a skin tumor and patients with an equivocal lesion on uncovered areas. It was concluded that while definite results concerning the impact of skin cancer screening on mortality and morbidity are missing, physicians should continue to perform opportunistic skin cancer screening.

New promises in adjuvant therapy of melanoma

Peter Hersey from the University of Sydney (NSW, Australia) presented an update on current trends in treating melanoma. A new development in adjuvant therapy in 2011 with IFN-α_2b was termination of the ECOG 1697 trial, as analysis after entry of 975 patients found no difference in recurrence-free or overall survival [101]. The second event of note in 2011 was approval by the US FDA of peg-IFN-α_2b (PegIntron) for the treatment of stage III melanoma based on the result of the EORTC 18991 trial, which found that PegIntron induced a significant increase in recurrence-free survival in patients with stage III melanoma [9]. Two other adjuvant therapy trials, the EORTC 18071 and DERMA trial, have completed accrual and results are pending. A current trial, ECOG 1609, is comparing treatment with Yervoy™ against standard high-dose IFN-2β. One of the major advances in treatment of melanoma has been the introduction of drugs that target mutated BRAF in patients with measurable metastatic melanoma. These drugs (Zelboraf™ [Roche]; approved by the US FDA and GlaxoSmithKline) have been associated with high response rates in up to 70% of patients. Moreover, a combination of the BRAF inhibitors with inhibitors of the MEK protein may induce even higher response rates and have fewer side effects. However, one of the limitations of the BRAF and MEK is the development of resistance to the drugs and relatively short periods of response, which contrasts with the effects of Yervoy anti-CTLA-4 antibodies, which induce low response rates but durable responses. It has been concluded that a number of new drugs and possible combinations are currently under investigation and that it is desirable that these trials will result in a substantial improvement in survival from melanoma.

Non-melanoma skin cancer

Another focus of this conference was related to the pathogenesis and diagnosis of non-melanoma skin cancer.

Pathogenesis, pathways & prevention of squamous cell carcinoma

Adèle Green from the Queensland Institute of Medical Research underlined that cutaneous squamous cell carcinoma (SCC) especially affects people over 40 years of age who sunburn easily without tanning, and people who are immunosuppressed. The major cause is excessive sun exposure, illustrated by the tenfold differences in incidence rates among people of similar heritage living in Australia (330/100,000) and the UK (33/100,000). Ultraviolet radiation acts as a carcinogen in several ways including causing DNA damage through signature mutations in tumor suppressor genes, DNA photoproducts and genomic instability, as well as local and systemic immune suppression. Pathways to SCC have been studied in mouse epidermal lineages and findings suggest that multiple hits are required to a cell in one of various compartments of the epidermis including hair follicle bulge cells and interfollicular epidermal stem cells to activate Ras signaling and inactivate p53, for example, by ultraviolet radiation [10].

Although actinic keratoses (AKs) are recognized as potential precursors of SCC, the true transformation rates are hard to measure and estimates vary widely from <0.1 to 0.6% per year. One of the most intensive clinical studies of the natural history of AK was performed in the Queensland community of Nambour, showing that very high regression rates of AKs can occur in prevalent AK within a 6-month period [11]. In 494 prevalent AKs and 614 incidents of AK, there was no transformation to SCC over an 18-month period of close follow-up. In the same Nambour study population, it has also been shown that prevention of SCC is directly achievable through sunscreen protection [12], while dietary factors and nonsteroidal anti-inflammatory medications are potential second-line preventives [13–15].

Iris Zalaudek presented the data of a recent study, in which the dermoscopic features of a series of histopathologically diagnosed facial cutaneous AK, intraepidermal carcinoma and invasive SCC were investigated and which revealed significant difference between these different stages within the continuum of SCC [16]. It was concluded that dermoscopy improves the diagnosis of non-melanoma skin cancer at different stages of progression.

The Skin Cancer Audit Research Database

The Skin Cancer Audit Research Database (SCARD) was presented by Cliff Rosendahl from the School of Medicine, University of Queensland (QLD, Australia). It is an initiative of the Skin Cancer College of Australia and New Zealand (SCCANZ), primarily designed to enhance patient safety by tracking specimens through the treatment cycle [17]. The registration for SCARD is free and is available to bona fide medical practitioners [102]. At this dedicated online internet-based version of the SCARD, physicians can record and track information regarding their specimens at each stage of management. The dataset (currently at >130,000 specimens) satisfies all ethics requirements for research and can be accessed at [103]. SCCANZ has also entered into a partnership with The University of Queensland which has incorporated SCARD into the curriculum for students of the Master of Medicine, Primary Care Skin Cancer Medicine course and Queensland University also provides academic support for data management and analysis and research. It was concluded that SCARD is a unique project which is proving to be a valuable asset for physicians who treat skin cancer. It has had a substantial uptake by Australasian primary care skin cancer practitioners and is being promoted internationally.

Financial & competing interests disclosure

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.

No writing assistance was utilized in the production of this manuscript.