Evaluating outcomes of alternative pathologic terminology in high-grade dysplastic colorectal lesions

Pathologists occasionally classify colorectal adenomas with dysplastic mucosal invasion as intramucosal carcinoma (IMC), or carcinoma in situ (CIS), instead of high-grade dysplasia (HGD), potentially leading to earlier surveillance colonoscopies and inappropriate surgical referrals. We aimed to analyze differences in the management of patients with these diagnoses, and examined the factors that may lead to inappropriate early interval (IEI) follow-up recommendations for surveillance.

We reviewed 870 colonoscopy and pathology reports from 2015-2022, excluding cases of colorectal cancer, inflammatory bowel disease, and lesions not amenable to endoscopic resection. Surveillance appropriateness was defined in accordance with the 2020 US Multi Society Task Force (USMSTF) guidelines. ANOVA and Fisher's exact tests were used to compare patient groups, while binary logistic regression identified predictors of IEI.

Among 233 patients analyzed, 86% had HGD, 12% IMC and 2% CIS. IMC (odds ratio [OR] 4.09, 95% confidence interval [CI] 1.52-11.5; P=0.01) and CIS (OR 3.70, 95%CI 0.57-29.7; P=0.17) had significantly higher IEI rates relative to HGD. Predictors of IEI included Black race (OR 2.39, 95%CI 1.17 - 5.03; P=0.02), en bloc resection (OR 10.9, 95%CI 3.53-49.0; P<0.001), and IMC (OR 4.09, 95%CI 1.52-11.50; P=0.01). No differences in surveillance outcomes were observed.

Endoscopic resection is curative for dysplasia confined to the mucosa in completely resected colonic adenomas. Labeling these lesions as "carcinoma" increases IEI recommendations without improving outcomes. Our findings support the 2020 USMSTF guidelines to standardize all dysplastic colorectal lesion terminology as HGD to ensure appropriate follow-up intervals.