Abstract

Background: Small bowel cancer (SBC) is one of the tumours associated with Lynch syndrome (LS). To advise on screening for this tumour it is paramount to be informed about the lifetime risk. The aim of this study was to calculate the lifetime risk of SBC in LS and to identify possible risk factors.

Methods: Clinical and pathological data were collected on 1496 proven or putative carriers of a mismatch repair gene mutation from 189 families. Kaplan-Meier survival analysis was used to calculate the lifetime risk and to assess potential risk factors.

Results: 28 (1.9%) of the 1496 (putative) mutation carriers were identified with SBC. The median age at diagnosis was 52 years (range 23–69 years). The lifetime risk of developing SBC was 4.2%. There was no difference in risk between males and females (log rank: p = 0.2470), or between MLH1 and MSH2 mutation carriers (log rank: p = 0.2754). SBC was not observed in MSH6 mutation carriers (n = 203). The previous occurrence of colorectal cancer and a family history of SBC did not increase the risk significantly.

Conclusions: Approximately, one out of 25 mutation carriers will develop SBC during life. No specific risk factors were identified. The risk appeared to be too low to advise screening by means of an invasive burdensome procedure like double balloon enteroscopy. However, screening by a non-invasive procedure (videocapsule endoscopy) might be considered if future studies will show its cost effectiveness. In patients with unexplained abdominal complaints and/or unexplained iron deficiency anaemia SBC should be considered.