Testicular function after cytotoxic chemotherapy: Evidence of Leydig cell insufficiency

Purpose: To evaluate testicular function in men after treatment with cytoto xic chemotherapy. Patients and Methods: We measured testosterone, sex hormone-binding globuli n (SHBG), luteinizing hormone (LH), and follicle-stimulating hormone (FSH) levels in 209 men after treatment with mechlorethamine, vinblastine, procar bazine, and prednisone, hybrid chemotherapy, or high-dose chemotherapy and in 54 healthy age-matched controls. Results: The mean age of the patients was 38 years (range, 19 to 68 years), and all patients had received chemotherapy between 1 and 22 years previous ly. Patients had significantly higher mean LH (7.9 v 4.1 IU/L; P < .0001) a nd FSH levels (18.8 v 3.1 IU/L; P < .0001) than controls. There was no sign ificant difference in mean total testosterone level between the patients an d controls, but there wets a trend toward a lower mean testosterone/SHBG ra tio in the patients (0.63 v 0.7; P = .08). Analysis of the hormonal paramet ers using a model that allowed for the effects of increasing age on testicu lar function showed evidence of significant recovery of gonadal function in the first 10 years after treatment. Fifty-two percent of patients had LH l evels at or above the upper limit of normal, and 32% of patients had increa sed LH with testosterone levels in the lower half of the normal range, sugg esting a degree of Leydig cell impairment. Conclusion: In a significant proportion of men, there is good evidence of L eydig cell dysfunction after cytotoxic chemotherapy. The clinical significa nce of this Leydig cell dysfunction is not clear, but some of these men may benefit from testosterone replacement. Further studies are warranted. J Cl in Oncol 17:1493-1498. (C) 1999 by American Society of Clinical Oncology.