AOS9 Mortality in children of women diagnosed with cancer: A population based cohort study

Abstract

Background With increasing risks of cancer and improving chances of survival, an increasing number of female survivors are starting or extending their family post-diagnosis. The mortality risks in the offspring of mothers with a history of cancer were evaluated. Methods From the Swedish Multi-generation Register and the Cancer Register, we identified all 174,893 children whose mothers had been diagnosed with invasive cancer between 1958 and 2001. For these children, we calculated relative risks of death (standardised mortality ratios, SMRs) compared with the background population and assessed trends in SMRs. Findings With the exception of offspring of mothers with tobacco-related cancers (head and neck, thoracic, cervical; SMR 1.23 [95% confidence interval (CI) 1.13–1.33]), offspring of mothers with a history of cancer did not have increased mortality risk (SMR 1.00 [95% CI 0.97–1.03]). Children born within 1 year of their mother’s diagnosis had an increased mortality risk (SMR 1.66 [95% CI 1.25–2.13]), particularly if their mother was primiparous at diagnosis of breast cancer (SMR of 11.07 [95% CI 2.09–27.13]). Offspring born more than 1 year after their mother’s diagnosis of haemopoietic cancer were also at increased risk of death (SMR 2.07 [95% CI 1.10–3.35]). Interpretation Timing of childbirth in relation to the mother’s diagnosis and type of cancer modifies mortality risks in the offspring. The increased mortality risk in children conceived around the time of the mother’s diagnosis suggests a negative effect of the cytotoxic treatment on the offspring, which primiparous women are more likely to accept than women who have given birth before. Despite the high relative risks, absolute increases in mortality risks are small. Funding M. Hartman was supported by NMRC/1180/2008 and NUS Start-up Fund DPRT (Grant No. R-186-000-108-133 ). This study was also funded by the Swedish Research Council (SIMSAM Grant No. 80748301 ). The authors declared no conflicts of interest.