IBD RAISES RISK OF SOME CANCERS

The risk for some cancers is elevated in people with inflammatory bowel disease (IBD) who are older and who have discontinued immunomodulators, according to new data presented here at the European Crohn's and Colitis Organisation 2018 Congress.

"Our IBD patients were at increased risk for biliary cancers, non-Hodgkin's lymphoma, and all lymphomas in general," said Thomas Greuter, MD, from University Hospital Zürich. But there was no elevated risk for other malignancies, such as breast, lung, and urogenital cancer, and melanoma," he pointed out.

"Treating physicians should be further aware of potential carcinogenic effects of immunomodulators," he said.

Greuter and his team assessed 3119 patients enrolled in the National Swiss IBD Cohort from 2006 to 2016. The proportion of males and females was similar, mean age at diagnosis was 28 years, and patients had IBD for a mean of 11 years. More patients had Crohn's disease than ulcerative colitis (57% vs 43%). Approximately 30% were receiving biologic treatment in March 2016, when the data were analyzed.

The researchers used both a cross-sectional analysis and a 5-year longitudinal follow-up to assess cancer in the study population. The goals were to identify the frequency, incidence, risk, and protective factors for cancer overall and for specific cancer subtypes. Investigators defined malignancy as a composite of cancer, leukemia or lymphoma, and intestinal dysplasia.

Unexpectedly, gastrointestinal cancers were the most frequently observed cancers in our cohort, followed by lymphoma, skin, and urogenital cancers.

A total of 122 patients (3.9%) were diagnosed with malignancy. "Unexpectedly, gastrointestinal cancers were the most frequently observed cancers in our cohort, followed by lymphoma, skin, and urogenital cancers," Greuter reported.

For the longitudinal analysis, only the 2580 patients without cancer at the time of enrollment and with at least one follow-up visit were included. Of these, 67 patients (2.6%) were diagnosed with a new malignancy over a median of 4.9 years.

The incidence rate of cancer was 439 per 100,000 patient-years, but after patients with dysplasia were excluded, that rate increased to 458 per 100,000 patient-years.

The investigators performed univariate and multivariate Cox regression modeling to identify predictors of cancer in the IBD cohort. Age and cessation of immunomodulators were significant predictors for the development of malignancy, whereas treatment with aminosalicylates and biologics were protective.

Table. Predictors of Malignancy

Factor	Hazard Ratio	P Value
Discontinuation of immunomodulators	2.813	<.001
Age	1.046	<.001
Current antibiotic use	3.377	.020
Intestinal surgery	1.805	.023
Biologic therapy	0.535	.020
Current 5-ASA therapy	0.485	.026
Discontinuation of 5-ASA therapy	0.299	.299

This was "a large IBD cohort with a long follow-up," said session moderator Jessica de Bruyn, MD, from the Academisch Medisch Centrum Universiteit in Amsterdam.

"It's very good to know all those risk factors in order to stratify and help our patients," she told Medscape Medical News. And it is good "to know which patients have the highest risk of developing cancer."

Recent studies have shown a decreasing trend for the incidence of colorectal cancer in IBD patients, Greuter pointed out. "Data on the frequency of extraintestinal malignancies are inconsistent, and the association between risk factors and cancer development is well established only for a few predictors."

"Although increased rates of melanoma have been described with the use of anti-TNF and close collaboration with dermatologists is clearly recommended, anti-TNF treatment does not seem to be a risk factor for the development of cancer overall, most probably because of better control of intestinal inflammation."

Greuter and de Bruyn have disclosed no relevant financial relationships. 

European Crohn's and Colitis Organisation (ECCO) 2018 Congress: Abstract OP037. Presented February 17, 2018.