Prophylactic cranial irradiation increases the risk of testicular damage in adult males surviving ALL in childhood.

By combining three series of Scandinavian patients, we were able to compare the late testicular sequelae in 41 adult males whose therapy had included chemotherapy alone or chemotherapy with cranial irradiation without other radiotherapy for ALL in childhood. In multivariate analysis, cranial irradiation was associated with a decrease of 5.7 (95% confidence limits 1.5-9.9) cm (P = 0.010) in height, and a decrease of 4.8 (0.3-9.2) ml (P = 0.036) in testicle size. Cyclophosphamide was associated with increases of 8.2 (-0.5-16.9) (P = 0.065) and 3.9 (0.3-7.4) U/L (P = 0.036) in serum FSH and LH concentrations, respectively. Of the 12 patients who had received both cranial irradiation and cyclophosphamide therapy, 4 (33%) had delayed pubertal development as compared with 1 (3.5%) of the other 29 patients (P = 0.008). Patients 12-16 years of age at diagnosis had larger testicles (P = 0.051) and higher testosterone concentrations (P = 0.026) than others. Neither sexual activity nor semen findings correlated with the preceding treatment. Our data indicate that prophylactic cranial irradiation may be associated with impaired growth and pubertal development in boys with ALL.