Phase I trial of weekly docetaxel with concurrent three-dimensional conformal radiation therapy in the treatment of unfavorable localized adenocarcinoma of the prostate.

PURPOSE: A phase I trial was conducted to determine the maximally tolerated dose (MTD) of concurrent weekly docetaxel and three-dimensional conformal radiation therapy (3-D CRT) in unfavorable localized adenocarcinoma of the prostate. PATIENTS AND METHODS: Patients with unfavorable localized adenocarcinoma of the prostate underwent daily 3-D CRT to a total dose of 70.2 Gy at 1.8 Gy/fraction and concurrent docetaxel given once a week for 8 to 9 weeks. The initial weekly docetaxel dose level was 5 mg/m(2) and the docetaxel doses were escalated as follows: 8, 12, 16, 20, and 25 mg/m(2).
RESULTS: Between January 2000 and August 2002, 22 men completed the chemoradiation therapy protocol. The dose-limiting toxicity was grade 3 diarrhea, which occurred in the first two patients treated at the 25 mg/m(2) docetaxel dose level. The MTD of weekly docetaxel was determined to be 20 mg/m(2). The overall incidence of grade 2 diarrhea and grade 2 dysuria was 36% and 23%, respectively. Seven (32%) and 15 (68%) patients did not experience any diarrhea or dysuria, respectively. No neutropenia or thrombocytopenia was observed. One patient required intermittent urinary catheterization 10 months postcompletion of therapy, which resolved without any surgical intervention. Seventeen patients remain in prostate-specific antigen remission. At a median follow-up interval of 8 months (range, 2 to 27 months), all patients are alive.
CONCLUSION: Concurrent weekly docetaxel in conjunction with 3-D CRT is well tolerated with acceptable toxicity. The MTD of weekly docetaxel was determined to be 20 mg/m(2) with concurrent 3-D CRT.