Prospects for the treatment of endocrine-responsive tumours.

Much has been achieved over the last 30 years to improve the treatment of hormone-dependent cancer of the breast, ovary and prostate. The development of the antioestrogen tamoxifen (Nolvadex) spear-headed a range of drugs that counter the growth-promoting action of the female and male sex steroid hormones. An important additional benefit of endocrine therapies has been their low toxicity compared with conventional cancer chemotherapy thereby providing effective treatment with few serious side-effects and a sustained quality of life. Although some currently available therapies improve patient disease-free survival and overall survival, particularly when given in an adjuvant setting, they are not cures. There is, therefore, a continued need to develop newer therapies that extend the effectiveness of those currently available. This is particularly important when tumours either fail to respond or develop resistance to endocrine therapy. In this review, we examine how our improved understanding of the factors that influence the progression of endocrine-related tumours is leading to the development of novel therapies to treat both hormone-dependent and -independent tumours.