Fertility of long-term male survivors of acute lymphoblastic leukemia diagnosed during childhood.

Fertility impairments among men treated during childhood for cancer are known to occur after some, but not all, types of anti-cancer therapy. This is the first study to evaluate proven fertility among adult male survivors of childhood acute lymphoblastic leukemia (ALL). In a retrospective cohort study, proven fertility (ever fathered a pregnancy) was evaluated by self-report among 213 men treated for ALL before age 18 on protocols of the Children's Cancer Group (CCG). Controls (N = 145) were drawn from among male siblings. Overall, with a proportional hazards analysis, proven fertility of male survivors was not different from that of controls (relative fertility (RF) = 0.95, 95% CI 0.63-1.43). However, married men treated before age 10 with high dose (24 cGy) cranial radiotherapy (RT), without spinal RT, had only 9% of the fertility of controls (Relative risk, RR = 0.09, 95% CI 0.01-0.82). High dose cranial RT at older ages was not associated with a statistically significant fertility deficit (RR = 0.56, 95% CI 0.25-1.28). In this first study of proven fertility among men treated for childhood leukemia, the majority of survivors showed no evidence of fertility impairment compared to controls. However, men treated at a young age with high dose cranial RT may have impaired fertility. These results suggest that further investigation of men with these treatments is needed to confirm and extend these findings.