Fertility treatment and childhood cancer risk: a systematic meta-analysis

To clarify the association between fertility treatment and the risk for cancer in children. Meta-analysis. None. Twenty-five cohort and case-control studies involving children born after fertility treatment as the exposure of interest and cancer as the outcome. None. Medline was searched through September 2012 to identify relevant studies. The study-specific estimates for each cancer outcome were combined into a pooled relative risk (RR) with 95% confidence interval (CI) by a meta-analytic approach. We found that children born after fertility treatment were at increased risk for all cancers (RR = 1.33; 95% CI, 1.08-1.63) and for hematological cancers (RR = 1.59; 95% CI, 1.32-1.91), central nervous system/neural cancers (RR = 1.88; 95% CI, 1.02-3.46), and other solid cancers (RR = 2.19; 95% CI, 1.26-3.80). For specific cancer types, we found increased risks for leukemias (RR = 1.65; 95% CI, 1.35-2.01), neuroblastomas (RR = 4.04; 95% CI, 1.24-13.18), and retinoblastomas (RR = 1.62; 95% CI, 1.12-2.35) associated with fertility treatment. The results of the largest meta-analysis on this topic to date indicate an association between fertility treatment and cancer in offspring. However, our results do not rule out that factors related to underlying subfertility, rather than the procedure itself, are the most important predisposing factors for childhood cancer.