To analyze the short-term outcomes of patients undergoing endoscopic submucosal dissection (ESD) for superficial colorectal neoplasms, and to identify predictors of malignant pathology of these lesions.

ESD was performed in 111 patients with 152 high-risk colorectal tumors [≥10 mm in diameter or laterally spreading tumor (LST) morphology]at the Peking University Cancer Hospital. We retrospectively reviewed the patient records, therapeutic outcomes, and procedure-related adverse events. We used univariate and multivariate analyses to identify the risk factors for malignancy.

There were 78 adenocarcinomas and 74 adenomas. The complete resection rates were 95.4% and 91.0% for all and malignant cases, respectively. Adverse events were confirmedor highly suspected in seven (4.6%) cases. As to the biopsy pathology,thefindings were consistent with the postoperative pathology in 99 (65.1%) lesions. The majority of malignancies (67.9%) were diagnosed as adenomas before resection. Older patients were more susceptible to developing malignant lesions (mean age, 64.4 vs 59.8 years in the carcinoma and adenoma group, respectively, P<0.001), and the tumor size was significantly larger in the malignant group (2.13 cm vs 1.45 cm, P=0.009). The proportions of malignant tumors were 67.5%, 49.0%, and 42.4% for rectal, left colon, and right colon lesions, respectively (P=0.045). Moreover, a significant difference was found according to morphology, with 63.2% of LSTs diagnosed as malignancies, compared to only 41.6% of protruding tumors (P=0.008).

ESD is a generally safe and effective procedure for treating colorectal neoplasms when performed by experienced endoscopists. Biopsy is not always reliable for the diagnosis. Several factors such as old age, large size, rectal location, and LST morphology are related to malignant pathology. For tumors with these high-risk factors, treatment with ESD instead of endoscopic mucosal resection should be considered to achieve enbloc resection.