Two recent studies focused on postpolypectomy surveillance methods in patients at intermediate risk for colorectal cancer and complications after polypectomy in patients prescribed antithrombotic medications.
In the first study, researchers enrolled participants in the English Bowel Cancer Screening Programme who were ages 60 to 72 years and deemed to be at intermediate risk of colorectal cancer following colonoscopy from January 2012 through December 2013. Eligible patients had had a positive guaiac-based fecal occult blood test and were scheduled to undergo surveillance with colonoscopy every three years, per British guidelines.
Program participants were offered fecal immunochemical tests (FIT) at one, two, and three years postpolypectomy, and those who completed a FIT at year one were included in the study (n=5,938). Those who tested positive (hemoglobin ≥40 µg/g) at years one or two were offered colonoscopy early, and all others were offered colonoscopy at three years. Researchers compared colonoscopy versus FIT surveillance by estimating diagnostic accuracy for colorectal cancer and advanced adenomas and calculating incremental costs.
Results were published online on Dec. 11 by Gut.
Overall, 97% of participants returned FITs at years two and three, and cumulative FIT positivity was 13%. Twenty-nine participants were diagnosed with colorectal cancer, and 446 were diagnosed with advanced adenomas. At three years, 725 (12.2%) of participants had colonic examination following positive FIT, which found colorectal cancer in 17 of 29 (58.6%) patients and advanced adenomas in 151 of 446 (33.9%) patients. At a lower threshold (10 µg/g), FIT positivity was higher (28.8%), with 72% sensitivity for detecting colorectal cancer and 57% sensitivity for detecting advanced adenomas.
Incremental costs per additional advanced adenoma and colorectal cancer detected by colonoscopy versus FIT surveillance were £7,354 and £180,778, respectively. The researchers estimated that in intermediate-risk patients, substituting colonoscopy every three years with low-threshold annual FIT could reduce the number of colonoscopies by 71%. However, annual FIT could miss 30% to 40% of colorectal cancers and 40% to 70% of advanced adenomas, depending on the threshold used.
The study authors noted limitations, such as the fact that they examined FIT performance only in relation to the first surveillance colonoscopy. “Our results suggest that FIT could perform a role in postpolypectomy surveillance of intermediate-risk patients. … Further research is warranted before decisions are made about whether it is reasonable to adopt FIT for surveillance,” they wrote.
In the second study, researchers used national data from a large insurance provider to identify adults who had colonoscopy with polypectomy or endoscopic mucosal resection from Jan. 1, 2011, through Dec. 31, 2015. They compared 30-day postpolypectomy complications (e.g., gastrointestinal [GI] bleeding, cerebrovascular accident, myocardial infarction, hospital admissions) of patients prescribed direct-acting oral anticoagulants (DOACs) (n=1,590), warfarin (n=3,471), and clopidogrel (n=6,443) versus 599,983 control patients who were not prescribed these medications.
Results were published online on Nov. 29 by Clinical Gastroenterology and Hepatology.
While postpolypectomy complications were uncommon, they occurred in a higher proportion of patients receiving any antithrombotic agent versus controls (P<0.001). In the DOAC group, the percentage of patients who had GI bleeding was 0.63% (95% CI, 0.30% to 1.20%) versus 0.20% (95% CI, 0.20% to 0.30%) of controls, and the percentage with cerebrovascular accident was 0.06% (95% CI, 0.01% to 0.35%) versus 0.04% (95% CI, 0.04% to 0.05%) of controls.
Clopidogrel, warfarin, bridge anticoagulation, higher CHADS2 score, Charlson Comorbidity Index, and endoscopic mucosal resection were associated with increased odds of complications. Patients prescribed DOACs no longer had a significant increase in the odds of GI bleeding, myocardial infarction, or hospital admission after adjustment for bridge anticoagulation, endoscopic mucosal resection, Charlson Comorbidity Index, and CHADS2 score.
The authors noted limitations of the study, including its retrospective design and the possibility that periprocedural medication management may have differed between the antithrombotic groups. “Patients with a higher CHADS2 score, comorbidity index, bridge anticoagulation use, or undergoing [endoscopic mucosal resection] may be at higher risk [for postpolypectomy complications],” they concluded. “Further studies on high-risk patients, optimal peri-procedural dosing, and bleeding prophylaxis are needed.”