Endoscopic Polypectomy For Malignant Polyps: Should Laterality Guide Clinical Decisions?
*Sonja Boatman1, *Catherine Tran2, *Sarah Bell2, *Genevieve Melton1, *Martin Weiser3, Sayeed Ikramuddin1, *Robert Madoff1, *Imran Hassan2, *Paolo Goffredo3
1University of Minnesota, Minneapolis, MN;2University of Iowa, Iowa City, IA;3Memorial Sloan Kettering Cancer Center, New York City, NY
OBJECTIVE(S): Current guidelines consider endoscopic resection as appropriate treatment for malignant colon polyps with negative margins, low grade histology, and no lymphovascular invasion (LVI). While an increasing body of literature has established the worse prognosis of advanced stage right-sided colon cancers following curative treatment, there is a paucity of data regarding the prognostic impact of laterality in patients undergoing endoscopic resection of T1 polyps. We hypothesized that the more aggressive biologic behavior observed in advanced disease for right-sided cancers would be similarly represented in malignant polyps, and that tumors in this location would be associated with lower overall survival (OS).
METHODS: The National Cancer Database was queried for adult patients with T1NxMx tumors and a single lifetime cancer diagnosis who underwent an endoscopic polypectomy between 2004 and 2017. Patient with positive margins and without follow up information were excluded.
RESULTS: A total of 2,337 patients met the inclusion criteria; 22% were right-sided polyps. Endoscopically excised proximal tumors were more common in elderly, black patients, and those with public insurance and higher number of comorbidities (all p<0.01). Among patients with complete pathologic data, there was no difference between the right and left side with a median size of 1 cm, >92% having no LVI, and 100% no tumor deposits. In univariate analysis, 5-year OS was 73% vs 86% for right vs left polyps (Figure 1; p<0.01). After adjustment for available confounders, right sided location remained significantly associated with worse OS (HR 1.49, 95% CI 1.21-1.83). Additional poor prognostic factors included older age, higher number of comorbidities, public insurance, and lower socioeconomic status.
CONCLUSIONS: In this national cohort of patients with T1 colon cancer undergoing endoscopic polypectomy only, we identified right colon location as an independent prognostic factor associated with 50% increased risk of mortality. Therefore, our data suggest that the location of the polyp should be taken into consideration along with other pathological characteristics when making clinical decisions regarding treatment and/or surveillance.
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