Retrospective cohort study of incidence of non-colorectal/endometrial malignancies in individuals with Lynch syndrome

Lynch syndrome (LS) is strongly associated with colorectal and endometrial cancers (CRC/EC), for which universal tumor screening (UTS) via mismatch repair proteins immunohistochemistry is recommended. Emerging evidence suggests an association between LS and several other tumor types. A retrospective cohort study at the University of Padova (Italy) investigated the incidence of non-CRC/ECs malignancies in LS individuals. Among 570 patients with LS diagnosed between 1995 and 2023, Non-CRCs/ECs accounted for 40% of all malignancies. The highest SIRs compared with the general population were observed for cancers of the small intestine (SIR 10.54; 95% CI 5.90-17.39), urothelium/kidney (7.55; 5.42-10.24), stomach (4.58; 2.90-7.16), ovary (3.80; 2.32-5.87), and pancreas (3.09; 1.61-5.18). The authors conclude that UTS starting with CRC and EC only is insufficient to identify patients with LS in the general population.