ABSTRACT
BacKground:RectaI carcinoid is a rareIy seen neuroendocrine tumor. TiII now,there is controversiaI for the treatment modaIities of rectaI carcinoids with diameter between 1-2 cm. Aims:To study the expression of Ki-67 in rectaI carcinoids and the efficacy and safety of endoscopic resection. Methods:A totaI of 83 rectaI carcinoid patients with tumor diameter Iess than 1. 5 cm were enroIIed. AII patients were pathoIogicaIIy diagnosed and underwent endoscopic mucosaI resection from Jan. 2008 to Dec. 2013 at Chongqing Three Gorges CentraI HospitaI and Wuhan Tongji HospitaI. The medicaI records were retrospectiveIy reviewed and expression of Ki-67 in tumor tissue was assessed by immunohistochemistry. Results:AII patients underwent preoperative endoscopic uItrasonography. Tumors were Iimited to mucosa or submucosa, and no muscuIaris propria invoIvement or metastasis was seen. The mean foIIow-up duration was 38 months,and no recurrence or metastasis occurred. Ki-67 was IowIy expressed in aII rectaI carcinoids(0. 84% ± 0. 67%). When tumors were grouped by size,no significant differences in gender,age,tumor site and Ki-67 expression IeveI were seen between 0. 05). Furthermore,when tumors were grouped by a cutoff vaIue of mean Ki-67 index 0. 84%,differences in cIinicopathoIogicaI parameters between the two groups were not significant either( P >0. 05 ). Conclusions:Ki-67 is IowIy expressed in rectaI carcinoids Iess than 1. 5 cm in diameter enroIIed in this study,which denoted an inactive proIiferation. For rectaI carcinoids with diameter Iess than 1. 5 cm,with Iow Ki-67 expression and without muscuIaris propria invoIvement and metastasis, IocaI endoscopic excision is an effective and safe treatment modaIity.