Population-based Swedish matched cohort study of lifetime risk of solid tumors and leukemia in individuals with Down sydrome

A population-based matched cohort study in Sweden investigated age- and subtype-specific cancer risks in individuals with Down syndrome (DS). National healthcare registers were used to identify 9742 DS individuals born in Sweden between 1930 and 2017. Each DS individual was matched by birth year, sex, and birth county to 50 DS-free individuals. Children with DS had a 20-fold increased risk of acute lymphoblastic leukemia and a nearly 500-fold increased risk of acute myeloid leukemia before the age of 5. In contrast, adult DS individuals had an overall lower risk of solid tumors, with significantly decreased risks for breast, prostate, lung, colorectal and gynecological cancer, and melanoma. However, an increased risk was observed for testicular cancer and chondrosarcoma/chondroblastoma.