Objective: To prospectively evaluate the time-course of recovery of serum testosterone levels after a short course of luteinizing hormone-releasing hormone analogue (LHRHa) and radical radiotherapy to the prostate.
Patients and methods: Testosterone, luteinizing hormone (LH) and follicle-stimulating hormone (FSH) were sequentially measured prospectively in 59 men who received short-course LHRHa treatment and radiotherapy for localized prostate cancer. Measurements were made before treatment (baseline), during LHRHa treatment, and at 6, 12, 18, 24 and >40 weeks after the last LHRHa injection.
Results: The median (range) time from the first to last LHRHa injection was 116 (54-194) days. The mean (95% confidence interval) testosterone levels (in nmol/L) at baseline, during treatment and at 6, 12, 18, 24 and >40 weeks afterward were 12.0 (10.8-13.1), 0.6 (0.5-0.7), 1.4 (0.6-2.2), 11.4 (9.7-13), 12.2 (10.5-14), 10.4 (8.9-12) and 11.7 (10.5-13). Four men had low baseline testosterone levels (<6.1 nmol/L). At 6 weeks after the last LHRHa injection, no men had testosterone levels in the 'normal' range; 35% were in the normal range at 12 weeks, 85% at 18 weeks, 89% at 24 weeks, and 96% at 1 year.
Conclusion: After LHRHa treatment and radiotherapy, the testosterone levels of most men had recovered to normal by 18-24 weeks after the last LHRHa injection.