289 What Differences Are There Between Early and Delayed Colonoscopy Following a Positive Stool DNA Test?

Abstract

INTRODUCTION: Previous stool DNA studies excluded patients who had their colonoscopy done more than 3 months after a positive stool DNA test. In this study, we compare patients who had early colonoscopy with patients who had delayed colonoscopy following a positive stool DNA test. METHODS: Review of 1413 patients who had a positive stool DNA followed by documented colonoscopy was done. Two patients were excluded because of finding of “other carcinoma” aside from adenocarcinoma. Attention was given to the date of the colonoscopy in regards to the date of the positive stool DNA result. Patients were divided in 2 groups. Group 1 included patients who had their colonoscopy within 3 months of the positive stool DNA test while group 2 included patients who had their colonoscopy at least 3 months after the positive stool DNA test. Only the index lesion was recorded. Advanced adenoma was defined as an adenoma that is larger than 10 mm or had high risk features such as villous transformation or high grade dysplasia. Nonadvanced adenoma was defined as an adenoma that is smaller than 10 mm and had no high risk features. Statistical analysis with Chi-square and Fisher exact was done to compare the proportions. A P-value < 0.05 was considered to be statistically significant. RESULTS: Out of the 1411 patients included in the study, 1144 (81.08%) patients had their colonoscopy done within 3 months of the positive stool DNA results, while 267 (18.92%) had it done at least 3 months after the positive stool DNA test. Between group 1 and group 2, “adenocarcinoma” was found in 1.75% vs. 1.5% respectively (P = 1.00). “Advanced adenoma” was found in 23.25% vs. 25.47% respectively (P = 0.44). “10 mm adenoma” was found in 6.91% vs. 8.24% respectively (P = 0.45). Non advanced adenoma was found in 29.11% vs. 31.09% respectively (P = 0.52). Finally, no adenomas were found in 38.99% vs. 33.71% respectively (P = 0.11). CONCLUSION: This study shows similar colonoscopy outcome in patients who have positive stool DNA test whether the colonoscopy was done within 3 months or longer than 3 months after a positive stool DNA test. In future studies, it is not necessary to exclude patients who had their colonoscopy done more than 3 months after a positive DNA test.