Cancer risk in IBD associated with age and recent immunomodulator use

Although IMM might contribute to an increased cancer risk (despite their control of the underlying chronic inflammation), available data remain inconsistent.

Cross-sectional and longitudinal analysis of the Swiss IBD cohort elucidated prevalence and incidence of cancer next to protective and risk factors, including the role of IMM. Data on IBD patients included between 2007 and 2013 were initially analysed in a cross-sectional manner. Patients with malignancies (=composite of cancer, dysplasia and lymphoma) were compared with controls.

A total of 122 malignancy cases (3.9%) were detected in a total number of 3,119 patients. Most patients had gastrointestinal carcinoma (23.0%), dysplasia (22.1%), or skin cancer (9.0%). Patients with malignancies were more often male, older at the age of diagnosis, and had longer IBD duration. Fistula, intestinal surgery, and surgery for fistula were more frequently reported. Cancer patients were more often found to be taking antibiotics and steroids, but medication with biologics was less frequently reported.

Data were analysed using a multivariate logistic regression model. Age (OR 1.04, P<0.001), UC (OR 1.68, P=0.03), intestinal surgery (OR 4.51, P<0.001), fistula (OR 1.74, P=0.015), and treatment with steroids (OR 2.13, P=0.001) were independent predictors for the presence of cancer. Treatment with 5-aminosalicylic acid (OR 0.61, P=0.036) and biologics (OR 0.38, P<0.001) were identified as protective factors.

In a second analysing step, only patients without malignancy at enrolment and a follow-up of ≥1 year were included to calculate risk of cancer development. Seen from this longitudinal perspective, 2.6% malignancy cases occurred in 2,580 patients not previously diagnosed with cancer. Based on a median follow-up of 4.9 years and a total follow-up of 12,420.8 patient-years, an incidence rate of 539/100,000 was calculated. CRC (17.9%), dysplasia (14.9%), skin malignancy (13.4%), and lymphoma (9.0%) were most frequently reported.

In a univariate Cox regression model, age, intestinal surgery, treatment with antibiotics, and recent use of IMM were predictors for the development of cancer. Treatment with 5-aminosalicylic acid and biologics were identified as protective factors. These factors remained significant predictors in a multivariate regression analysis [2].