探讨经肛门内镜显微手术(transanal endoscopic microsurgery，TEM)在不同特点的中低位直肠癌器官保留中的应用。

回顾性分析北京协和医院于2017年1月至2023年10月间收治的81例行TEM术或采用TEM平台行经肛全直肠系膜切除术(transanal total mesorectal excision, taTME)的直肠癌患者资料。

患者根据临床和病理特征被分为三组：早期直肠癌行TEM术组(A组)、进展期直肠癌新辅助治疗(neoadjuvant chemoradiotherapy，nCRT)后行TEM术组(B组)、进展期直肠癌采用TEM平台行taTME组(C组)。A组32例，临床分期cT1N0，均行TEM术；切除后具有高危因素者追加根治性手术或辅助放化疗。8例为肠镜切除后追加TEM术，术后病理均未见肿瘤。中位随访时间37.5个月(4～84个月)，无病生存30例(93.75%)。B组36例，nCRT后达到cCR或near-cCR，行TEM术。术后病理ypT0 21例(58.3%)、ypT1 4例(11.1%)、ypT2 10例(27.8%)、ypT3 1例(2.8%)。中位随访时间56个月(12～80个月)，无病生存26例(72.2%)。C组13例，临床分期为cT3^＋NanyM0或cTanyN^＋M0，所有患者nCRT后，采用TEM平台行taTME术。中位随访时间48个月(4～68个月)，无病生存11例(84.6%)。三组患者年龄、体质量指数(body mass index，BMI)差异无统计学意义(P＝0.818、0.934)。A、B组间肿瘤大小、距肛门距离、ASA差异有统计学意义(P＝0.011、0.015、0.001)。B、C组间肿瘤大小、ASA差异有统计学意义(P<0.001、P＝0.0276)。三组间5年无进展生存期比较，A、B组间差异有统计学意义(P＝0.034)，A、C组间差异无统计学意义(P＝0.053)，B、C组间差异无统计学意义(P＝0.534)。

TEM技术在中低位直肠癌保肛手术中具有重要作用，低危早期直肠癌可完整切除；对于有高危因素者，可在术后追加辅助放化疗。对于局部进展期直肠癌，如行nCRT后肿瘤退缩不明显，可以TEM为平台行taTME术，实现低位保肛，但并发症较多；如达到cCR或near-cCR且患者保肛意愿强烈，可考虑行TEM术，但可能牺牲无进展生存时间。

To explore the application of transanal endoscopic microsurgery (TEM) in organ preservation for mid-low rectal cancer with different characteristics.

Retrospective analysis of the data of 81 patients with rectal cancer treated using TEM technology at Peking Union Medical College Hospital between Jan. 2017 and Oct. 2023.

Patients were divided into three groups based on clinical and pathological characteristics: early-stage rectal cancer patients undergoing TEM surgery (Group A), advanced rectal cancer patients undergoing TEM surgery after neoadjuvant chemoradiotherapy (nCRT) (Group B), and advanced rectal cancer patients undergoing taTME surgery using the TEM platform (Group C). Group A included 32 patients with clinical staging of cT1N0, all undergoing TEM surgery. Patients with high-risk factors after resection received additional radical surgery or adjuvant chemoradiotherapy. Eight patients underwent TEM surgery following polypectomy, and no tumors were found in the postoperative pathology. The median follow-up time was 37.5 months (ranging from 4 to 84 months), with 30 patients (93.75%) achieving disease-free survival. Group B included 36 patients who achieved cCR or near-cCR after nCRT and subsequently underwent TEM surgery. Postoperative pathology results showed ypT0 in 21 patients (58.3%), ypT1 in 4 patients (11.1%), ypT2 in 10 patients (27.8%), and ypT3 in 1 patient (2.8%). The median follow-up time was 56 months (ranging from 12 to 80 months), with 26 patients (72.2%) achieving disease-free survival. Group C included 13 patients with clinical staging of cT3⁺ NanyM0 or cTanyN⁺ M0 rectal cancer. All patients underwent nCRT followed by taTME surgery using the TEM platform. The median follow-up time was 48 months (ranging from 4 to 68 months), with 11 patients (84.6%) achieving disease-free survival. There were no significant differences in age and BMI among the three groups (P=0.818, 0.934). Significant differences were found between Groups A and B in tumor size, distance from the anus, and ASA (P=0.011, 0.015, 0.001). Significant differences were also observed between Groups B and C in tumor size and ASA (P<0.001, P=0.0276). In terms of 5-year progression-free survival, there was a significant difference between Groups A and B (P=0.034), no significant difference between Groups A and C (P=0.053), and no significant difference between Groups B and C (P=0.534).

TEM plays a crucial role in organ preservation for mid-low rectal cancer. It can resect low-risk early rectal cancer. For patients with high-risk factors can be followed by adjuvant therapy. For cT2N0 patients neoadjuvant therapy followed by TEM can be performed. For locally advanced rectal cancer where the tumor does not significantly shrink after nCRT, taTME surgery on the TEM platform can achieve low-level sphincter preservation. For patients who achieved cCR or near-cCR after nCRT and with strong desire for sphincter preservation, TEM can be considered, but it may sacrifice progression-free survival time.