Chemotherapy of advanced prostatic cancer. Evaluation of response parameters.

A total of 125 patients with progressing advanced prostatic cancer were entered into a chemotherapy study comparing cyclophosphamide, 5-fluorouracil, and standard therapy. Parameters of response were studied in 110 patients who could be evaluated. Thirty-six patients (33 per cent) were considered to have an objective response, that is becoming stable (29 patients) or in partial regression (7 patients). Negative response parameters (predictors of a poor response to chemotherapy or standard theraphy leading to progress) included (1) bone marrow evidence of prostatic cancer, (2) abnormal liver scan, (3) prior radiation therapy (indirectly through increased toxicity to chemotherapy), and (4) lack of bilateral orchiectomy prior to randomization. Positive indicators (predictors of good responses) included (1) reduction of primary tumor mass, especially after administration of 5-fluorouracil or cyclophosphamide, and (2) hemoglobin values. There were more objective responders to cyclophosphamide than standard therapy whether the hemoglobin was initially normal or low. Indeterminate parameters of response included weight gain, presence of bony or soft tissue metastases, relief of pain, performance status, excretory urography, and biochemical determinations of liver and renal function.