BACKGROUND. 5-fluorouracil (5-FU) is a known radiosensitizer that enhances efficacy, in vivo and in vitro, when administered during radiotherapy. The following study was performed to evaluate the toxicity of continuous infusion 5-FU administered concomitant with brachytherapy in patients with locally advanced prostate cancer.
METHODS.
Over a 26-month period, a total of 25 patients with newly diagnosed, locally advanced prostate cancer underwent radioactive gold (Aulg8) brachytherapy. Twenty-four of 25 patients were surgically staged and confirmed node negative. AuIg8 seed placement was performed transperineally under fluoroscopic and ultrasonographic guidance using an average of 195 mCi of Au"*. Within 4 hours after seed placement, 25 patienrs received 5-FU administered as a continuous infusion over 4 days, at 1 of 8 dose levels ranging from 200-1100 mglm'lday. Patients had clinical follow-up for a minimum of 1 year. Decreases in serum prostate specific antigen (PSA) and prostate volume (normalized to pretreatment values) were determined at 12 months.
Results
. 5-FU associated toxicity was negligible, with Grade 1 nausea in four patients and no Grade 2 or higher toxicity. No unique locoregional toxicity was noted. At 12 months after treatment, PSA values decreased on average to 16.4% of pretreatment values. Twelve-month prostate volumes decreased to 55% of the pretreatment values.
CONCLUSIONS. These findings suggest that continuous infusion 5-FU can be administered safely concomitant with brachytherapy at doses up to 1100 mg/m2 per day for 4 days. Cancer 1996; 7R924-7.