A RANDOMIZED COMPARISON OF THE CLINICAL AND HORMONAL EFFECTS OF 2 GNRH AGONISTS IN PATIENTS WITH PROSTATE-CANCER

Objective: The aims of the study were (i) to compared the efficacy of the two long-acting GnRH agonists (GnRHa) triptorelin (Trp) and leupro lide (Leu) in men with prostate cancer and (ii) to assess the pattern of plasma testosterone levels following each injection of GnRHa. Patie nts and Methods: 67 patients referred for prostate cancer not suitable for surgery were randomly allocated to two treatment regimens: 33 pat ients received 3.75 mg Trp i.m. at 4-week intervals for 3 months and 3 4 patients were treated with 3.75 mg Leu s.c. at the same rhythm of ad ministration for 3 months. Results: Clinical data at entry and assesse d monthly during follow-up did not differ between the two groups. Plas ma prostate-specific antigen (PSA) and testosterone were measured befo re, 24 and 72 h after each injection of GnRHa. During treatment, PSA d ropped similarly in both groups. By month 2, testosterone was < 1.0 nm ol/l in 77 and 48% of patients treated with Trp and Leu, respectively (p = 0.02). 24 and 72 h after GnRHa injection, 77 (Trp) and 56% (Leu) of patients had testosterone <1.0 nmol/l (p < 0.05). Conclusions: The second and third injections of GnRHa were not followed by a significan t increase in testosterone. Trp induced a higher decrease in testoster one than did Leu. The implications in terms of survival should, howeve r, be studied in a larger and longer study.