Chapter 19 – Breast and Prostate Cancers: A Comparison of Two Endocrinologic Malignancies

Prostate and breast cancers are two common malignancies that have some striking and surprising similarities. As we know, they are both tumors of accessory sex organs and both are characterized primarily by being epithelial, hormone-driven malignancies, which respond to so-called “endocrine therapy.” They constitute the second leading cause of cancer-related mortality in the United States for men and women, respectively. In both cancers, there is often a latency period spanning many years from the time of diagnosis of the primary tumor to the development of metastasis. Recent research has revealed that both breast and prostate cancer are complex and heterogeneous disease processes that encompass multiple pathologies with variable treatment options, as opposed to one distinct disease with a uniform treatment. A great deal of experimental and clinical research has been undertaken for each of these cancers resulting in many new strategies of care. Until recently, this has been truer for breast cancer than for prostate cancer. This is partly due to the fact that breast cancer was recognized centuries before prostate cancer, and that it is a more accessible organ. More important reasons are the early vigorous advocacy of breast cancer survivors for research support and the misconception that prostate cancer was an “old man’s disease” meriting little concern. More recently, support for and progress in prostate cancer research has greatly expanded.