Clinical Use of Inhibin B in Male Adolescent Childhood Cancer Survivors: Correlation With Cyclophosphamide Equivalent Dosing.

INTRODUCTION

Alkylators are gonadotoxic in a cumulative manner, with overall exposure quantified as the cyclophosphamide equivalent dose (CED). Inhibin B is used as a surrogate marker of fertility in adult male childhood cancer survivors (CCS) treated with alkylators, but information about its relationship with CED over time in the adolescent population is lacking.

OBJECTIVE

To examine whether CED is negatively associated with inhibin B among adolescent male CCS.

METHODS

This is a retrospective observational study of 110 male CCS at higher risk for infertility. Both predictors for inhibin B values and their variability over time per patient were assessed.

RESULTS

CED and inhibin B1 ( r = -0.24, P = 0.03) and B2 ( r -0.27, P = 0.02) are negatively correlated. When CED was dichotomized into 2 groups (< or ≥4 g/m 2 ), patients who received lower doses were found to have significantly higher inhibin B than those with higher doses ( P = 0.03).

CONCLUSIONS

Our data corroborates previous research, showing a significant association between inhibin B and CED; however, no other significant predictors of inhibin B were identified. More research is needed to determine whether male CCS with unexpectedly low inhibin B levels have poor sperm quality.