Chemotherapy for endocrine-therapy-refractory prostate cancer.

The effects of various chemotherapy regimens on endocrine-therapy-refractory prostate cancer were examined in 64 patients. Chemotherapy was started from the first evidence of relapse. The regimens of the initial chemotherapy were as follows: cisplatin (CDDP, 4 cases) and ifosfamide (4 cases) were given as single agents and vincristine, ifosfamide, and peplomycin (VIP, 8 cases); cyclophosphamide, doxorubicin, and CDDP (CAP, 14 cases); ifosfamide, doxorubicin, and CDDP (IAP, 24 cases); and etoposide, doxorubicin, and CDDP (EAP, 10 cases) were given as combinations. On the basis of the results, the patients were divided into two groups: single agents plus VIP and other combinations. In the CAP, IAP, and EAP groups, the cause-specific survival was similar, and the survival of these groups was longer than that of the single agents plus VIP group. Since patients with a long duration between the start of endocrine therapy and the start of chemotherapy were contained in the CAP, IAP, and EAP groups, comparison was performed without these cases. No difference was found between the two groups, suggesting that no superior regimen was found. The short-term effect was evaluated on the basis of the changes observed in prostate-specific antigen (PSA) and prostatic acid phosphatase (PAP) levels at 3 months after the start of chemotherapy, and patients showing a complete response, partial response, or no change on any of the regimens exhibited longer survival than did those with progressive disease. Since the PSA doubling time estimated before the chemotherapy correlated with the change in the PSA values due to the chemotherapy, the rate of proliferation of the tumor influenced the effect of the chemotherapy. Thus, this finding suggests that slowly growing cancers show a better response to chemotherapy than do rapidly proliferating ones.

RCT Entities:   Population Interventions Outcomes