Chapter 5: Cancer Trends in Sweden Until 2010

Abstract

To arrive at a reasonable estimate of the total need for radiotherapy, the various descriptions of population trends and measures of cancer trends must be studied concurrently. Incidence and mortality are well documented by official statistics. All prognoses are based on these measures, the official population statistics, and the 1989 population prognosis from Statistics Sweden. Incidence, mortality, and prevalence may be considered either individually or together as indirect measures of the need for radiotherapy at different stages for different types of cancer.

Incidence, ie, the number of cases of disease onset during a given period, shows the indirect need for curative radiotherapy, eg, for breast cancer, laryngeal cancer, gynecological tumor types, and head and neck cancer. The projected average annual mean increase in total incidence is 1.0%.

Mortality may be used as an indirect measure of the need for palliative treatment for recurring cancer, eg, for bone metastases, prostate cancer, lung cancer, or breast cancer. The mean increase is estimated at 0.9% per year.

Likewise, prevalence can be an indirect measure of the need for palliative treatment for cancer diseases of a chronic nature, eg, prostate cancer and multiple myeloma. The total mean increase per year has been estimated at 2.0%.

The total need for radiotherapy in the future should be viewed against the background of all these descriptive measures. Assessment must also consider numerous other factors that directly influence need. A change in the indications for treatment can quickly increase the need for radiotherapy, eg, the benefits of radiotherapy for noninvasive breast cancer are currently being studied. Even a change in the indications for surgical intervention for small tumors in the breast influence the need for primary curative radiotherapy in this large group of patients. Likewise, a shift in staging the primary diagnosis, eg, in head and neck cancer, and changes in fractionation (hyperfractionation) may substantially influence need. This is addressed further in another section of the report.

The largest single group of cancer patients who receive radiotherapy are those with bone metastases (25% of the total). The size of this group, and thereby the potential unsatisfied need, is largely unknown since no statistics show the prevalence of metastases in the population. This group is comprised mainly of patients that were primarily diagnosed with prostate cancer, breast cancer, and lung cancer. Concerning lung cancer, incidence trends probably provide the best measure of changes in the number of bone metastases over time. The annual increase in incidence has been estimated at 1.5%. As for breast cancer and prostate cancer, mortality trends provide more information about trends in the number of bone metastases. Both types of cancer increased by 1.9% per year. Chapter 6 presents the types of cancer for which radiotherapy is usually given. The projected trends show that each of these cancer diagnoses, except lung cancer in men and cervical cancer in women, are expected to increase in number until the year 2010. Prevalence is expected to increase even more, particularly cancer in the rectum, breast, and prostate. Also, the number of cases of non-Hodgkin's lymphoma is expected to nearly double by 2010.