Risk of second gonadal cancers in women and children with germ cell tumors

BACKGROUNDMen with testicular cancer have an increased risk of developing cancer in the contralateral testis, but the risks of second gonadal cancers (SGCs) in women and children treated for germ cell tumors (GCTs) have not previously been quantified. METHODSThe incidence of SGCs was ascertained in patients who had survived for at least 1 year after GCT diagnosis using data from the Surveillance, Epidemiology, and End Results SEER 9 registries (1980-2012). Relative risks of SGCs were estimated separately for boys, women, and girls compared with men based on Poisson regression analysis. RESULTSThe cohort included 21,546 individuals (1116 boys, 827 women, 622 girls, and 18,981 men). A total of 25 SGCs were identified in boys, 1 in women, and 2 in girls compared with 254 in men. The risk of SGC in postpubertal boys (aged 10 years) was comparable to that of adult men (boys: standardized incidence ratio, 15.90; 95% confidence interval, 10.29-23.47; men: standardized incidence ratio, 10.88; 95% confidence interval, 9.58-12.30). However, no SGCs were observed in boys who were diagnosed with a testicular GCT before age 10 years (N = 179). An elevated risk of SGC was also not observed for women or girls. CONCLUSIONSThe apparent lack of an SGC in prepubertal boys suggests that susceptibility is either age-dependent and/or histology-dependent. The sex differences in the risk of SGC suggest differences in the etiology of ovarian versus testicular GCT. The finding that the risk of SGCs in postpubertal boys is similar to that observed in men indicates that long-term follow-up for SGC is warranted in postpubertal boys. Cancer 2016;122:2076-82. (c) 2016 American Cancer Society. Postpubertal boys and men with germ cell tumors share a similar risk of developing a second testicular cancer. However, neither prepubertal boys with testicular cancer nor females with ovarian germ cell tumors appear to have an increased risk of second gonadal cancer.