Lupo PJ, et al. - The role of perinatal and familial factors on the risk of soft tissue sarcomas (STS) was examined in a large population-based birth cohort. Researchers linked the 4,023,436 individuals in the Swedish Birth Registry born during 1973-2012, to the Swedish Cancer Registry, where incident STS cases were identified. From Statistics Sweden, perinatal and familial factors, including fetal growth, gestational age, and presence of a congenital malformation, were obtained and evaluated. STS was diagnosed in 673 individuals in 77.5 million person-years of follow-up. STS was more frequently diagnosed in those with congenital malformations and other adverse birth outcomes compared to their unaffected contemporaries. These associations suggest that the risk of STS is influenced by disrupted developmental pathways and genetic factors.