Prostate cancer is the development of neoplasia in the prostate, a major gland in the male reproductive system. While most prostate cancers grow slowly, some can develop relatively quickly and aggressively. In a later stage of the disease, cancer cells may disseminate from the prostate to other organs of the body, particularly the bone, lung, brain and lymph node. Prostate cancer initially cause no symptoms, but in an advanced stage it can cause difficulty in urinating, blood in the urine, or pain in the pelvis. A non-malignant or precursor form of prostate cancer known as benign prostatic hyperplasia may produce similar symptoms, although it is essentially not invasive.
Many prostate cancer patients can be safely followed with active surveillance or watchful actions. However, the major forms of clinical treatments include a combination of surgery, radiation, hormone therapy or chemotherapy. If it only occurs inside the prostate, the disease is generally curable. However, when cancer cells have spread to the bones, cytotoxic or harsh therapies are necessary. Outcomes depend on a person's age and other health conditions as well as how aggressive and extensive the cancer is. Most people with prostate cancer do not end up dying from the disease, and the 5-year survival rate in the United States is approximately 99%. To date, it is the 2nd most common type of malignancy and the 5th leading cause of cancer-related death in men. In 2012 it affected 1.1 million men and claimed 307,000 deaths. Prostate cancer occur more frequently in the western countries or developed world, but incidence rates have been continuously arising in the developing countries. Clinical detection increased significantly in the 1980s and 1990s in the global range due to development of the gold standard--PSA testing. Studies of males who died from unrelated causes have found prostate cancer in 30% to 70% of those over the age of 60.
Most hormone-naive prostate cancers become resistant to treatments after 1-3 years and resume growth despite hormone therapy, a condition termed as "hormone-refractory prostate cancer" (HRPC) or "castration-resistant prostate cancer (CRPC)". The most prevalent chemotherapeutic agent docetaxel (Taxotere) has been used as a standardized modality for CRPC and provides a median survival benefit of 2-3 months. A second-line chemotherapy involves cabazitaxel. Although combination of bevacizumab, docetaxel, thalidomide and prednisone appears effective in the treatment of CRPC, these agents are usually used after the occurrence of CRPC, not before. Thus, whether or not these patients should receive chemotherapy prior to development of CRPC, and whether this approach can prevent the aggressive progression of the disease to a treatment refractory status, remain largely open but intriguing questions.
In this study, investigators performed a Phase I, single agent exploration, multicenter clinical trial to establish the treatment efficacy of several chemotherapeutic agents in patients with high risk localized prostate cancer who have developed the primary cancer in prostate. Up to 5 cohorts have been enrolled to determine the effectiveness and safety of single therapeutic strategy. Besides the five-year disease-free survival, overall survival and five-year metastasis-free survival post treatment, investigators also take into account the anticancer agent-induced tumor stroma damage extent, which may provide further evidence to support the treatment efficacy and assess the potential influence of a damaged tumor microenvironment on disease progression or regression in clinical settings.
