Moke DJ, et al. - In this case–control study, researchers assess the risk for second malignant neoplasms (SMN) in correlation with obesity during childhood cancer treatment, given that obesity represents a recognized modifiable risk factor related to adverse outcomes in children with cancer. Using the California Cancer Registry, they identified patients (with SMN; n = 59) and controls (with a single-primary cancer; n = 130). They matched controls 3:1 to patients at the registry level by clinical factors. The median age at primary cancer diagnosis was 6 years. In the study sample, 64.5% were male and 31.7% were obese or overweight. The median time from primary cancer to SMN was 7.5 years. Findings revealed a possible association of obesity during childhood cancer treatment with increased risk for SMNs, especially among those obese during therapy.