Background: Various guidelines suggest indications for performing additional colectomy with en bloc removal of regional lymph nodes after endoscopic resection for T1 colon cancer. The aim of this study was to evaluate the pathologic outcomes of patients with surgical treatment after endoscopic resection for T1 colorectal cancer.
Methods: We used data from 275 patients who had undergone curative resection for T1 colorectal cancer at a single institution between 1991 and 2009. We evaluated the rationale for additional surgical treatment after endoscopic resection performed on 68 of the 275 patients and the association between various clinicopathologic features and lymph node metastasis.
Results: The 5-year overall survival rate was 96.3 %. Reasons for additional surgical treatment included an endoscopic specimen with a pathologically positive margin (n = 20), lymphovascular invasion (n = 25), and submucosal invasion depth of ≥ 1,000 μm (n = 23). When endoscopists failed to find macroscopic cancer residue during endoscopic resection, no pathologically residual cancer was found in the resected specimens. Histologic grade was an independent risk factor for lymph node metastasis (p = 0.028). In the absence of lymphovascular invasion, patients with well-differentiated T1 colorectal cancer did not have nodal involvement.
Conclusions: Although the outcomes of patients with additional surgical treatment after endoscopic resection for T1 colorectal cancer were satisfactory, excessive and unnecessary treatments may have been performed. Additional surgical treatment after endoscopic resection for T1 colorectal cancer might be unnecessary for patients with well-differentiated adenocarcinoma and no lymphovascular invasion.