Cooperative clinical trials of the National Prostatic Cancer Project: Protocol 900.

In May 1978, the National Prostatic Cancer Project Treatment Subgroup activated its first clinical trial evaluating adjuvant chemotherapy (Protocol 900). This protocol is a comparison of long-term adjuvant chemotherapy with cyclophosphamide, estramustine phosphate, or no additional treatment in patients with definitive surgical therapy for adenocarcinoma of the prostate. To date, 128 patients have been entered with an entry rate of approximately 2.2 patients per month. One hundred five patients form the basis of this report, with 96 patients still on active therapy. Estramustine phosphate has been administered at a dose of 600 mg/m2 orally daily in three divided doses. The cyclophosphamide is administered 1 g/m2 intravenously every 3 weeks. Results are still preliminary; only two evaluable patients have died. Approximately two-thirds of patients entered have had negative lymph nodes. Recurrent disease has been documented in 15 patients, including eight receiving cyclophosphamide, three receiving estramustine phosphate, and four on the no-treatment arm. The recurrence rate has been disproportionately high (50%) in patients receiving cryosurgery rather than radical prostatectomy (12%). Maximum survival has reached 241 weeks. Side effects have consisted of leukopenia in patients receiving cyclophosphamide (56%), and nausea and vomiting with cyclophosphamide (85%), and estramustine phosphate (36%). This study continues with patient entries now over one-half of the number anticipated in the original study design.