RESUMO
Objective:To examine the factors related to residual rectal neuroendocrine tumor at the margins after endoscopic resection.Methods:A retrospective case control study was conducted.From January 1, 2013 to March 31, 2018, data on 81 middle-aged and elderly patients with rectal neuroendocrine tumor aged ≥45 years who underwent endoscopic resection at the Endoscopic Center of the First Hospital of Jilin University were retrospectively collected.Based on whether residual tumor existed on histopathological examination, they were divided into the residual group(n=22)and the non-residual group(n=59). The causes of residual rectal neuroendocrine tumor at the margins after endoscopic resection were analyzed.Results:The diameters of lesions in 81 patients with rectal neuroendocrine tumors ranged between 0.3-1.5(0.73±0.33)cm.Postoperative histopathological examination revealed that all lesions were G1 neuroendocrine tumors, with residual tumor seen at the margins in 22 cases(27.2%). The mean tumor diameter was(0.78±0.36)cm for the residual group and(0.68±0.28)cm for the non-residual group, with no statistical significance between the two groups( t=1.320, P>0.05). Of the 22 patients in the residual group, 2 cases showed muscularis propria involvement and 14 cases showed tumor infiltration into the submucosa but without lymph node infiltration or metastasis, and in the rest of the cases lesions were confined to the mucosa.None of the 59 patients in the non-residual group had involvement of the muscular layer, but 23 cases showed tumor infiltration into the submucosa(39.0%)and the rest had lesions confined to the mucosa.The difference between the two groups was statistically significant( χ2=11.010, P<0.01). The results of binary Logistic regression analysis suggested that tumor infiltration into or beyond the submucosa( β=1.285, P<0.05)and the absence of preoperative ultrasonographic evaluation( β=-1.147, P<0.05)were independent risk factors for residual rectal neuroendocrine tumor at the margins after endoscopic resection. Conclusions:Tumor infiltration into the submucosa or beyond and lack of preoperative ultrasound evaluation are independent risk factors for residual rectal neuroendocrine tumor at the margins after endoscopic resection.