Clinical Course of Submucosal Colorectal Cancers Treated By Endoscopic Mucosal Resection

Abstract

Background/Aims: Although the risk of lymph node metastasis is known to be increased in deep submucosal invasion, some submucosal colorectal cancers with negligible risk of lymph node metastases can be cured by endoscopic mucosal resection (EMR). The purpose of this study was to investigate the clinical course of submucosal colorectal cancers treated by EMR. Methods: We retrospectively reviewed the medical records of patients who underwent EMR for colorectal neoplasms. Pathologically proven submucosal colorectal cancers were enrolled in the analysis. Results: A total of 52 patients (32 men, mean age 62 years) were enrolled between March 2001 and February 2007. In one patient, two submucosal cancers were identified. Forty seven lesions were located in left side colon and majority of lesions (n = 44) were protruded types. EMR was performed for 47 lesions and endoscopic submucosal dissection (ESD) for 6 lesions. Mean long diameter of resected specimens was 17.8 ± 8.3 mm. Histologic examination showed moderately-differentiated adenocarcinoma in 35 lesions, and well-differentiated adenocarcinoma in 18 lesions. Complete resection rate was 79.2%. Among 52 patients, 22 patients underwent additional surgery and 1 patient underwent radiation therapy due to one or more of following poor prognostic factors: involvement of resection margin, deep submucosal tumor invasion, or lymphovascular tumor emboli. Regional lymph node metastasis was detected in 4 out of 22 patients (18.2%) who underwent additional surgery. Among 25 tumors which were treated by radical endoscopic resection and followed-up by endoscopy, no local tumor recurrence was detected after a mean endoscopic follow-up period of 18.0 months (range 2.1∼53.3 months) with a mean of 2.4 follow-up endoscopies (range 1∼5). Hepatic metastasis was identified in one patient who rejected additional surgery despite cancer-positive resection margin at 26 months after EMR. Minor bleeding and perforation developed in 10 and 1 during 53 procedures, respectively. Endoscopic hemostatic procedures were successfully performed for minor bleeding episodes and perforation was also successfully managed with endoscopic clipping. Conclusions: Endoscopic resection seems to be feasible for the treatment of selected cases of submucosal colorectal cancers. Long-term follow-up with larger number of subjects is needed for elucidating the role of endoscopic treatment for submucosal colorectal cancers.