Background: Meta-analyses and guidelines recommend that deep submucosal invasion (>1 mm) of malignant sessile colonic polyps is an important risk factor for lymph node metastasis. However, existing data are based on small retrospective studies with marked heterogeneity. We herein aimed to investigate the long-term outcomes of patients who underwent complete endoscopic mucosal resection (EMR) of malignant colonic sessile polyps invading the submucosal layer.
Methods: Endoscopy records for the period 2000-2016 were reviewed retrospectively. All enrolled patients exhibited an endoscopically resected malignant colonic sessile polyp. All patients were advised to undergo surgery, but some opted for conservative treatment and endoscopic follow up.
Results: Fifty-one patients with confirmed infiltrative submucosal adenocarcinoma in sessile colonic polyps that had undergone complete EMR were detected. A total of 32 (62.7%) patients opted for surgery after EMR and 19 (37.3%) chose endoscopic follow up. In 44 (86.3%) patients the submucosal invasion was >1 mm. Residual malignant disease was identified in the surgical pathological specimen of only 1 patient. During a median follow up of 23.41 months (interquartile range 33.45, range 1.84-144.92), no local recurrences or lymph node metastasis were identified. Forty-nine patients are alive without evidence of disease and 2 died of other causes (without evidence of local or metastatic disease at last follow up).
Conclusion: Our data suggest that complete EMR of cancerous colonic sessile polyps, even in cases of submucosal invasion >1 mm carries a low risk of recurrence and therefore may need further evaluation as an alternative strategy to surgical resection.
Keywords: Malignant polyp; endoscopic mucosal resection; submucosal invasion.