Introduction

Chronic inflammatory bowel diseases (IBD), such as Crohn's disease and ulcerative colitis, are associated with an increased risk of various cancers, particularly colorectal cancer, but also other types, such as small intestine, biliary tract, or liver cancers. Additionally, certain extra-digestive cancers may also occur in patients with these conditions. These risks vary depending on the duration and severity of inflammation, as well as other factors such as family history or exposure to certain treatments. This work explores the diversity of cancers associated with IBD, their prevalence, and their clinical characteristics, highlighting the importance of considering these risks in the medical management of patients.

Aims & Methods

This is a retrospective and descriptive single-center study conducted within a hepatogastroenterology department, focusing on patients followed for inflammatory bowel diseases (IBD) who developed cancer. The study covers the period from 1990 to 2025.

Results

Out of a total of 1,795 patients followed for IBD (1,200 for Crohn's disease and 595 for ulcerative colitis), 2% (36 patients) developed cancer. The male-to-female sex ratio was 0.38, with a clear female predominance. Among the patients, 69.4% (25) had Crohn's disease, and 30.55% (11) had ulcerative colitis.
The most common location of Crohn's disease was colonic involvement (44%, 11 cases),the predominant phenotype was inflammatory (52%, 13 cases) ,for ulcerative colitis the most frequent location was left-sided colitis (54%, 6 cases) ,the median disease duration before the onset of cancer was 60 months.
Digestive cancers were the most commonly associated with IBD (38.8%, 14 cases), followed by breast cancer in women (30.5%, 11 cases), gynecological cancers (11.1%, 4 cases), prostate adenocarcinoma (5%, 2 cases), skin cancers (5%, 2 cases), and other cancers (5%, 2 cases).
Only 30.5% (11 patients) had risk factors (chronic smoking, family history of cancer, etc.).
Regarding treatment, 33% (12 patients) were on biologic therapy , 30.5% (11) were on azathioprin , 16.6% (6) were on therapeutic abstention , 8.3% (3) were on aminosalicylates, and 5.5% (2) were on corticosteroids.
Treatment was discontinued in 63.8% (23) of patients after the discovery of cancer, and 22% (8) experienced a flare-up which was successfully managed with corticosteroid therapy.
Eighty-three point three percent (83.3%, 30 patients) underwent surgical treatment alone or in combination with radiochemotherapy. Sixteen point six percent (16.6%, 6 patients) were at an advanced stage and had metastases, so they received palliative treatment.
Thirty-six percent (36%, 13 patients) had a good outcome, 30.5% (11) were lost to follow-up, and 2.7% (1) died.

Conclusion

The study shows a 2% cancer incidence in IBD patients, slightly higher than the general population's risk (0.3–0.5% annually), likely due to prolonged inflammation and disease duration. These findings highlight the need for enhanced cancer surveillance and preventive strategies, especially for patients with colonic involvement.