Surveillance Colonoscopy in IBD Tied to Lower Advanced Cancer Risk

Inflammatory bowel disease (IBD) patients diagnosed with colorectal cancer (CRC) had better cancer outcomes when they had undergone a recent surveillance colonoscopy, a retrospective study of military veterans found.

In the analysis of over 550 such patients, surveillance colonoscopy in the 6 months to 3 years prior to the CRC diagnosis was associated with a lower likelihood of late-stage cancer compared with no prior surveillance colonoscopy:

• 6 months to 1 year: adjusted odds ratio (aOR) 0.40, 95% CI 0.20-0.82 (P=0.01)
• 1 to 3 years: aOR 0.56, 95% CI 0.32-0.98 (P=0.04)

And patients with a surveillance colonoscopy in the year prior to their CRC diagnosis had lower all-cause mortality, regardless of IBD type or duration (adjusted hazard ratio [aHR] 0.56, 95% CI 0.36-0.88, P=0.01), reported Jason Hou, MD, MS, of the Baylor College of Medicine in Houston, and colleagues, writing in Clinical Gastroenterology and Hepatology.

“Our findings support current practice guidelines that recommend colonoscopy intervals from 1 year to 3 years among patients with IBD who have extensive colitis or left-sided colitis,” the group wrote.

Hou and colleagues noted that IBD patients are at greater risk for CRC, yet only about a fourth undergo routine colonoscopy surveillance, and the comparative benefit of different intervals for colonoscopy in IBD patients remains unknown.

For their study, they examined National Veterans Health Administration data on 566 IBD patients who were diagnosed with CRC from 2000 to 2015. Patients were grouped based on the timing of their last surveillance colonoscopy prior to their CRC diagnosis: 6 months to 1 year (n=55), 1 to 3 years (n=100), 3 to 5 years (n=18), or never (n=393).

Those with a follow-up of 1 year or more after their CRC diagnosis or who died within the first year were included. Patients who had a prior colectomy, secondary CRC diagnosis, dysplasia, or carcinoma in situ were excluded. Analyses adjusted for demographic confounders, as well as age at CRC diagnosis, IBD type, IBD duration and extent of involvement, comorbidity score, primary sclerosing cholangitis status, and tobacco or alcohol abuse, among other factors.

Three-fourths of the cohort were white, 98% were men, half were smokers, and about two-thirds had a comorbidity score of 0.

The average age at IBD diagnosis was 54 years (ulcerative colitis in 63%, Crohn’s disease in 34%). For CRC, the average age at diagnosis was 68 years: 30% had stage 0-II disease, 30% had stage III/IV disease, and the rest had an undetermined stage.

Most patients received treatment for their CRC (87%), though those with late-stage cancers were less likely to receive treatment (OR 0.24). Overall, 70% of the patients died during the study period, with 23% of the deaths being related to CRC.

Reached for comment, Dana Lukin, MD, PhD, of Weill Cornell Medicine in New York City, noted that the study “did not use prospectively evaluated endoscopy — so preparation quality, true disease extent, severity, and phenotype, and disease activity assessments were not possible.”

The authors acknowledged other limitations to the data as well, including that most patients were eligible for surveillance colonoscopy because of their age, potentially minimizing the observed benefit. Participants were also identified by ICD-9/ICD-10 codes, which could underestimate diagnoses and mortality.