Alterations in hormone levels after adjuvant chemoradiation in male rectal cancer patients.

Purpose: To evaluate follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone levels after postoperative chemoradiation in men with rectal cancer.

Methods And Materials: Forty-three men with rectal cancer had baseline and postchemoradiation FSH, LH, and testosterone measured. Adjuvant chemoradiation consisted of two 5-day cycles of bolus 5-fluorouracil (5-FU) every 4 weeks at a dose of 500 mg/m(2)/d followed by concurrent chemoradiation followed by two additional 5-day cycles of 5-FU at a dose of 450 mg/m(2)/d. Continuous-infusion 5-FU at 225 mg/m(2)/d was given during radiation. Pelvic radiation consisted of a three- or four-field technique with a median dose of 54.0 Gy in 30 fractions.

Results: Median follow-up was 6.1 years. Mean baseline FSH levels increased from 5.3 to a peak of 23.9 IU/L (p < 0.001) 13-24 months after chemoradiation. Mean baseline LH levels increased from 4.3 to a peak of 8.5 IU/L (p < 0.001) within 6 months after chemoradiation. Mean testosterone levels decreased from 15.4 nmol/L at baseline to 8.0 nmol/L more than 4 years after chemoradiation. Mean testosterone to mean LH ratio decreased from 4.4 at baseline to 1.1 after 48 months posttreatment, suggesting a continued decrease in Leydig cell function with time. Testicular dose was measured in 5 patients. Median dose was 4 Gy (range, 1.5-8.9 Gy).

Conclusions: Chemoradiation in men with rectal cancer causes persistent increases in FSH and LH levels and decreases in testosterone levels.