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Higher colon cancer risk tied to delayed colonoscopy after positive FIT
WASHINGTON — Patients who wait longer to undergo colonoscopy screening after a positive fecal immunochemical test are at higher risk for developing colorectal cancer, according to research presented at Digestive Disease Week.
“The fecal immunochemical test has been widely used in a nationwide program for the prevention of colorectal cancer,” Yi-Chia Lee, MD, PhD, of National Taiwan University Hospital said in his presentation. “However, in comparison with the primary colonoscopy, there’s a time lag between the positive FIT result and the follow-up colonoscopy.”
To determine how far CRC can progress between a positive FIT test and a follow-up colonoscopy, Lee and colleagues analyzed data from 94,884 patients who had positive FIT tests as part of a biennial FIT screening program in Taiwan between 2004 and 2012. Researchers classified the patients based on their time to colonoscopy: 0–3 months, 3–6 months, 6–9 months, 9–12 and more than 12 months. They determined that 9,033 patients were diagnosed with any kind of CRC, and 2,163 were diagnosed with advanced CRC.
Using 0–3 months — the recommended time for a follow-up colonoscopy — as a baseline, Lee and colleagues determined adjusted odds ratios for any kind of CRC for 3-6 months (aOR = 0.93, 95% CI, 0.85–1.02), 6–9 months (aOR = 0.85: 95% CI, 0.7–1.04), 9–12 months (aOR = 1.01; 95% CI, 0.73–1.4) and more than 12 months (aOR = 1.66; 95% CI, 1.18–2.32).
When accounting for just advanced-stage CRC, they found adjusted odds ratios of 0.84 (95% CI, 0.70-1.01), 1.22 (95% CI, 0.88-1.7), 1.32 (95% CI, 0.76-2.29), and 1.73 (95% CI, 0.94-3.17) for each group, respectively.
Lee and colleagues said their findings show that patients who don’t undergo a follow-up colonoscopy within the recommended three months following a positive FIT test, have a higher risk for developing CRC and advanced CRC.
“After positive FIT results, early colonoscopic follow-up is still required to decrease the stage shifting of already present colorectal cancer even though the overall number of colorectal cancers may increase modestly within one year,” Lee said. - by Alex Young
Reference:
Lee Y, et al. Abstract 98. Presented at: Digestive Disease Week; June 2-5, 2018; Washington, D.C.
Disclosures: Lee reports no relevant financial disclosures. Please see the DDW faculty disclosure index for a list of all other authors’ relevant financial disclosures.
Perspective
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The United States Multi-Society Task Force on Colorectal Cancer (MSTF) recommends tier 1 methods of colorectal cancer screening including colonoscopy or fecal immunochemical testing (FIT) be offered to eligible individuals. When choosing FIT, physicians should inform patients that annual FIT is suggested for optimal test performance and colonoscopy is required to evaluate a positive FIT result.
The MSTF suggest that the colonoscopy completion rate be 80% or greater for patients with a positive FIT for greatest effectiveness. Unfortunately, data demonstrates a wide variability in colonoscopy completion in individuals with a positive FIT test. Modeling data, based upon 10 million average-risk, screening eligible Americans showed an increase in CRC incidence of 0.3%/month, every additional month until colonoscopy was performed after a positive FIT, compared with individuals who received a colonoscopy within 2 weeks. Additionally, CRC mortality was estimated to increase by 1.4% for every month delay.
The study by Lee and associates assessed the clinical impact of a delay in colonoscopy after a positive FIT in Taiwanese patients. When compared to patients who had follow up colonoscopy within 3 months, individuals who had a delay in colonoscopy had a 3% increased adjusted risk of CRC (aOR 1.03, 95% CI: 1.01-1.06) and a 6% increased adjusted risk of advanced stage CRC (aOR 1.06, 95% CI: 1.02-1.10) per month. These data highlight the importance of establishing systems to ensure patients and organizations who choose and offer FIT testing understand the implications of a positive FIT and have mechanisms to navigate patients efficiently for their colonoscopy.
References: Robertson DJ, Lee JK, Boland CR, et al. Recommendations on Fecal Immunochemical Testing to Screen for Colorectal Neoplasia: A Consensus Statement by the US Multi-Society Task Force on Colorectal Cancer. Am J Gastroenterol 2017;112:37–53
Reinier G. S. Meester, Ann G. Zauber, Chyke A. Doubeni,et al. Consequences of Increasing Time to Colonoscopy Examination After Positive Result From Fecal Colorectal Cancer Screening Test. Clinical Gastroenterology and Hepatology 2016;14:1445–1451