Study: NOSES could achieve good short-term and oncological outcomes for colorectal cancer patients

This study is led by Prof. Xishan Wang (Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College), Prof. Chuangang Fu (Shanghai East Hospital, Tongji University School of Medicine), Dr. Xu Guan (Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College), Dr. Xiyue Hu (Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College) and Prof. Zheng Jiang (Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College), on behalf of China NOSES Alliance.

With the rapid development of minimally invasive surgery for the treatment of colorectal diseases, novel surgical techniques aiming at reducing surgical trauma have become frequently discussed issues. By avoiding auxiliary abdominal incision for specimen extraction, natural orifice specimen extraction surgery (NOSES), including transvaginal specimen extraction (TVSE) and transanal specimen extraction (TASE), is thought to be one of the least invasive options in the treatment of colorectal cancer (CRC).

However, most previous studies concerning the safety and effectiveness of NOSES are single-centered with limited sample sizes. Whether previous findings can be generalized to a wider patient population remains unclear.

This study performed the first nationwide large-scale study to confirm the safety and feasibility of NOSES for CRC by analyzing the short-term and long-term oncological outcomes. CRC patients who received the NOSES procedure as the primary therapy between August 2008 and May 2021 were registered in this database. All patients were pathologically diagnosed with malignancy.

A total of 5055 CRC patients who underwent NOSES were identified in the database. The overall postoperative complication rate was 14.1%. For rectal cancer, the complication rates of TASE and TVSE were 15.3% and 11.5%, respectively (P = 0.107). The rectovaginal fistula rate for TVSE was significantly higher than TASE (2.1% vs 0.4%, P = 0.005). For colon cancer, the complication rates of TASE and TVSE were 11.1% and 11.3%, respectively (P = 0.924), and there was no difference in all subtypes of complications between TASE and TVSE. These results reveal that the incidence of postoperative complications after NOSES was consistent with that reported in previous studies concerning CLS.

After exclusion of patients with a follow-up period of < 12 months and patients without follow-up data, 701 patients were left for survival analysis with a median follow-up of 25.3 months. The 3-year OS, 3-year DFS, and 3-year LRR were 93.2%, 82.2%, and 3.6%, respectively. These data show that NOSES does not result in a poor oncological prognosis in terms of long-term survival, thus further confirming the oncological safety of NOSES.

Also, a systematic review was performed to compare the short-term and oncological outcomes between NOSES and CLS, and 17 studies were included for further analyses. This review has shown that compared with CLS, NOSES presented lower complication rates and several advantages in postoperative recovery, which mainly include earlier postoperative flatus time and shorter hospital stay.

In summary, this is the first national database analysis report confirming that NOSES could achieve good short-term and oncological outcomes for CRC patients. However, NOSES should be performed cautiously by experienced surgeons in selected CRC patients.