Review of phase II hormone refractory prostate cancer trials

In men with hormone refractory metastatic prostate cancer, single agents have demonstrated an objective response when using a response rate greater than standard treatment in prior National Prostate Cancer Project (NPCP) trials. Among these agents are methotrexate, cisplatin, 5-fluorouracil, cyclophosphamide, doxorubicin, estramustine, methyl N-(2-chloroethyl)-N'-cyclohexyl-Nnitrosourea (CCNU), 5-(3,3-dimethyl1-triazenyl)1H-imidazole-4-carboxamide (DTIC), and vinblastine. Other combinations of protocols have been previously evaluated. Currently under review is a 1 4-year follow-up on an adjuvant trial (NPCP 900/1000) where all patients had a bilateral pelvic lymphadenectomy. These patients were then randomized to surgery or radiation, and received either cyclophosphamide, estramustine, or no therapy for 2 years. Clinical results showed there was no difference in disease-free survival or survival rates between those patients in the group who had T3 prostate cancer, and those with negative pelvic lymph node dissection. The drugs diethylstilbestrol, megestrol, or streptozocin have been used. In clinical trials, the single agent diethylstilbestrol usually had a better effect. Combinations of estramustine with vinblastine were also effective when compared with the results of standard treatment. When comparing patients who relapsed from hormone refractory prostate cancer, there was no significant statistical response rate difference (P = <0.05) in patients who were offered either flutamide or estramustine. To determine more accurately the positive results from these trials, the pre-prostate-specific antigen (PSA) era of stable disease must be re-evaluated.