Risk of incident cancer in patients with Inflammatory Bowel Disease with prior breast cancer: a multicenter cohort study

Abstract

Background and AimsBreast cancer is the most common malignancy observed in patients with inflammatory bowel diseases (IBD). The aim of our study was to evaluate incident cancer rate (recurrence or new-onset cancer) in a cohort of IBD patients with a history of breast cancer according to the subsequent IBD treatment provided. MethodsA multicenter retrospective study included consecutive IBD patients with prior breast cancer. The inclusion date corresponded to the diagnosis of index malignancy. Follow-up lasted from cancer diagnosis until the occurrence of incident cancer. ResultsAmong 207 patients included (median disease duration: 13 years [IQR 6 - 21]), first line treatment (median interval of 28 months [IQR 7 - 64]) was a conventional immunosuppressant in 19.3 % of patients, anti-TNF in 19.8 %, vedolizumab in 7.2 % and ustekinumab in 1.9 %.After a median follow-up of 71 months [IQR, 34 - 148], 42 (20%) incident cancers were observed (34 breast cancer recurrences). Adjusted incidence rates per 1000 person-years were 10.2 (95%CI 6.0- 16.4) for the untreated arm and 28.9 (95%CI 11.6-59.6) for exposed patients (p= 0.0519). There was no significant difference between treated patients and controls regarding incident-cancer free survival rates (p=0.4796). In multivariable analysis, factors associated with incident cancer were stage T4d (p=0.036), triple negative tumor (p=0.016) and follow-up of less than 71 months (p=0.005). ConclusionWe did not find a statistically significant increase in incident breast cancer related to IBD treatment beyond the already known poor prognostic factors of breast cancer.