Incidence and risk factors for neoplasia in inflammatory bowel disease

Inflammatory Bowel Disease (IBD) patients may have an increased risk of neoplasia. The aim was to evaluate the incidence of malignant neoplasia in IBD patients, associated risk factors and therapy adjustments.

Unicentric retrospective cohort study. All patients followed for IBD in a tertiary portuguese hospital and oncological centre during 2015-2020 were included.

318 patients were included female 55.0%, age at diagnosis = 37.24(±15,28), Crohn's disease 52.5%, Primary Sclerosing Cholangitis n = 7, family history of cancer n = 12, previous diagnosis of neoplasia n = 23(7.2%). 42 cancers were diagnosed in 35 patients (11.0%) - median of 12.0(IQR = 7.5-21.0) years after IBD diagnosis. Most affected organs were the skin (n = 15 in 11 patients; melanoma = 1), colon/rectum (n = 8 in 6 patients), prostate (n = 4), breast (n = 3) and anal canal (n = 2). In those with non-melanoma skin cancer, 6 were under active treatment with azathioprine and 2 had stopped it for more than two years. In the univariate analysis, the occurrence of neoplasia was positively associated with tobacco exposure (p = 0.022), age at IBD diagnosis (p = 0.021), and negatively with infliximab exposure (p = 0.046). In 9 cases, cancer treatment was different because of the IBD, while IBD treatment was changed in 9 patients. In those affected by cancer, in the univariate analysis, its cure/remission was negatively associated with tobacco exposure (p = 0.004) and positively with salicylates use (p = 0.007).

In IBD patients, cancer mostly affected the skin and the lower digestive system. As in the general population, tobacco exposure was a risk factor for the development of neoplasia.