Abstract: Objective To investigate the curative effect of natural orifice specimen extraction surgery （NOSES） on left colon cancer and the risk factors affecting prognosis. Methods Sixty patients with left colon cancer in our hospital from January 2016 to January 2019 were enrolled in the retrospective analysis and divided into an observation group （NOSES） and a control group （conventional radical operation）. Relevant operation indices and complications between the two groups were compared, and the factors affecting prognosis were analyzed. Results The observation group showed longer operation time as well as less intraoperative blood loss, postoperative anal exsufflation time, and hospital stay than the control group did （P<0.05）; the incidence rate of complications in the observation group was lower than that in the control group （10.0% vs. 33.3%, P<0.05）. The results of single factor analysis and multiple logistic regression model showed that tumor differentiation degree, tumor stage, tumor location, postoperative chemotherapy, and lymph node metastasis were the independent factors affecting the prognosis of patients with left colon cancer （P<0.05）. Conclusion NOSES is an effective surgery for left colon cancer, producing less complications. Special attention should be paid to tumor differentiation degree, tumor stage, postoperative chemotherapy, and lymph node metastasis, so as to improve the overall curative effect.

Key words: Natural orifice specimen extraction surgery, Colon tumor, Curative effect, Prognosis, Risk factors