Semen quality and spermatozoal DNA integrity in survivors of childhood cancer: a case-control study

Background Treatment of childhood cancer can result in impaired spermatogenesis. Intracytoplasmic sperm injection (ICSI), however, can enable men to achieve fatherhood, and has focused attention on gamete integrity in men with oligozoospermia. Our aim was to assess testicular function in survivors of childhood cancer. Methods We assessed testicular function in 33 survivors of childhood cancer and 66 age-matched controls. The median age at diagnosis and at the start of the trial was 10.0 years (range 2.2-16.9) and 21.9 years (16.5-35.2), respectively. We assessed pubertal staging, measured plasma sex steroid hormone concentrations, and analysed semen quality, including spermatozoal DNA integrity. Findings Ten (30%) individuals were azoospermic and six (18%) oligozoospermic (sperm concentration <20 x 10(6)/mL). Sperm concentration was significantly lower in the non-azoospermic group than in controls (median 37.1 x 10(6)/mL, IQR 19.7 x 10(6) to 89.9 x 10(6), vs 90.7 x 10(6)/mL, 50-5 x 10(6) to 121.5 x 10(6); p = 0.002). In the non-azoospermic cancer survivor group, inhibin B concentrations were lower than in controls (mean 153.3 ng/L, SEM 17.8, vs 223.7 ng/L, 8.8; p < 0.001), and FSH concentrations were higher (6.6 U/L, 0.9, vs 3.2 U/L, 0.2; p < 0.001). Only 11 (33%) survivors of childhood cancer had normal semen quality. There was no significant difference in sperm DNA integrity between the non-azoospermic and control groups (9%, 5-13, vs 11%, 7-16; p = 0.06). Interpretation Sperm concentration is reduced after treatment for cancer. However, the sperm produced seems to carry as much healthy DNA as those produced by the healthy population, suggesting that assisted conception can be considered as a treatment option for these men.