The antihormonal preventive therapy of breast cancer and prostate cancer.

With the continuing increase of median life expectancy of important segments of the world's population, cancer incidence, as well as cancer related morbidity and mortality, are constantly increasing, especially for developing countries and for breast and prostate cancer, the predominant gender-associated cancer types. In addition to continuing, with more and more expensive efforts to develop new and more effective cancer treatments, it is health-politically and medico-professionally important to realise that only successful approaches to primary cancer prevention of major and frequent cancer types will be able to change this socially and economically unfavourably outlook. It is therefore encouraging to see that primary (or pharmacologic, interventional) cancer prevention programs have been successfully developed over the past decade for individuals at elevated risk for breast and prostate cancer on the basis of several scientifically well-conducted, prospective chemoprevention trials, mainly with synthetic anti-hormones (anti-estrogens and anti-androgens) in the USA, in Europe and Australia. This paper summarises the presently published results and design of several completed and some currently running primary cancer prevention trials in breast cancer and prostate cancer, and also points to the important obstacles for their conduct and translation into general practice in the broader populations at risk outside of clinical prevention research.