Total mesorectal excision (TME) is an effective surgical method to reduce the local recurrence of rectal cancer and improve patient prognosis. However, there is debate about which surgical platform to use to achieve the best surgical outcome for TME. The emergence and technological progress of transanal total mesorectal excision (taTME) can solve the problem of difficulty in lower rectal resection and achieve better surgical resection results. Based on relevant literatures and combined with team clinical practice, the authors explore the technical advantages and oncological efficacy of taTME in rectal cancer.

Objective:To investigate the specimen quality of intersphincteric resection with transabdominal transanal mixed approach for rectal cancer in the Chinese Transanal Total Mesorectal Excision Registry Collaborative (CTRC) database.Methods:The retrospective case-control study was conducted. Based on the concept of real-world research, the clinicopathological data of 281 pati-ents with rectal cancer in the CTRC database who underwent intersphincteric resection with trans-abdominal transanal mixed approach in 19 medical centers, including the Beijing Friendship Hospital of Capital Medical University et al, from November 15,2017 to December 31,2023 were collected. There were 196 males and 85 females, aged 61(range, 27-87)years. Observation indicators: (1) preoperative examinations; (2) neoadjuvant therapy; (3) postoperative examinations; (4) analysis of influencing factors for positive circumferential margin in surgical specimen of intersphincteric resec-tion for rectal cancer. Measurement data with normal distribution were represented as Mean±SD. Measurement data with skewed distribution were represented as M(range). Count data were described as absolute numbers or percentages. The chi-square test was used for univariate analysis. Logistic regression model was used for multivariate analysis. Results:(1) Preoperative examinations. Of the 281 patients, 234 cases underwent preoperative pelvic magnetic resonance imaging (MRI) examina-tion. There were 2 cases in clinical stage T0, 3 cases in clinical stage T1, 58 cases in clinical stage T2, 137 cases in clinical stage T3, 24 cases in clinical stage T4, 3 cases in clinical stage Tx, 7 cases missing clinical T staging data. There were 87 cases in clinical stage N0, 68 cases in clinical stage N1, 60 cases in clinical stage N2, 9 cases in clinical stage Nx, 10 cases missing clinical N staging data. There were 30 cases with mesorectal fascia invasion, 53 cases with extramural venous invasion. The distance from lower margin of tumor to anal margin was 41.9(range, 1.0-80.0)mm. (2) Neoadjuvant therapy. Of the 281 patients, 125 cases underwent neoadjuvant therapy, including 39 cases receiving chemo-therapy alone, 6 cases receiving short-course simultaneous chemoradiotherapy, 5 cases receiving short-course simultaneous chemoradiotherapy and delayed surgery, 48 cases receiving long-course simultaneous chemoradiotherapy, 2 cases receiving other treatments, and 25 cases missing neoadju-vant therapy data. (3) Postoperative examinations. Of the 281 patients, 249 cases achieved R 0 resection, 9 cases achieved R 1 resection, and there were 23 cases missing surgical margin data. The maximum tumor diameter, the number of lymph nodes harvested and positive rate of vessel carcinoma embolus were 30.0(range, 0.5-200.0)mm, 13(range, 0-70) and 27.55%(73/265) in 281 patients. There were 252 patients with circumferential margin records, showing positive in 15 cases, with a positive rate as 5.95%(15/252). The minimum distance from deep part of tumor to circumferential margin was 7.0(range, 0-150.0)mm in 252 patients. There were 85 cases with distal margin records, showing positive in 1 case, and the distance from lower margin of tumor to distal margin was 10.0(range, 0-202.0)mm. There were 273 patients with specimen integrity records, which showed intact specimen in 208 cases, fair specimen in 58 cases, poor specimen in 4 cases, unevaluated specimen in 3 cases. There were 7 cases with rectal perforation. Of the 281 patients, cases in pathological stage T0, Tis, T1, T2, T3, T4 were 14, 5, 22, 107, 113, 12, respectively, and there were 8 cases missing pathological T staging data. Of the 281 patients, cases in pathological stage N0, N1a, N1b, N1c, N2a, N2b were 176, 27, 27, 11,20, 12, respectively, and there were 8 cases missing pathological N staging data. Of the 281 patients, there were 4 cases with distant metastasis, 262 cases without distant metastasis, 5 cases not evaluated, and 10 cases missing tumor metastasis data. Of the 125 patients undergoing neoadjuvant therapy, there were 85 cases with tumor regression grade records, including 16 cases as grade 1, 27 cases as grade 2, 19 cases as grade 3, 15 cases as grade 4, 8 cases as grade 5. (4) Analysis of influencing factors for positive circumferential margin in surgical specimen of intersphincteric resection for rectal cancer. Results of univariate analysis showed that preoperative T staging on preoperative pelvic MRI, mesorectal fascia invasion, extramural venous invasion, pathological T staging, and pathological N staging were related factors for positive circumferential margin in surgical specimen of intersphincteric resection for rectal cancer ( P<0.05). Conclusions:Intersph-incteric resection with transabdominal transanal mixed approach has good specimen quality and low positive rate of surgical margin. T staging on preoperative pelvic MRI may be related to positive circumferential margin after intersphincteric resection for rectal cancer.

Objective:To analyze the quality of surgical specimens of rectal cancer in the Chinese transanal total mesorectal excision (taTME) registry collaborative (CTRC) database.Methods:The retrospective and descriptive study was conducted. Based on the concept of real-world research, the clinicopathological data of 1 761 patients with rectal cancer in the CTRC database who underwent taTME in 40 medical centers, including the Beijing Friendship Hospital of Capital Medical University et al, from November 15, 2017 to December 31, 2022 were collected. There were 1 212 males and 549 females, aged 62(range, 53-68)years. Observation indicators: (1) preoperative examinations; (2) neoadjuvant therapy; (3) postoperative examinations. Measurement data with skewed distri-bution were represented as M(range). Count data were described as absolute numbers. Results:(1) Preoperative examinations. Of the 1 761 patients, 1 324 patients underwent preoperative pelvic magnetic resonance imaging examination, and the results showed that 4 cases as clinical T0 stage, 30 cases as clinical T1 stage, 250 cases as clinical T2 stage, 828 cases as clinical T3 stage, 141 cases as clinical T4 stage, 11 cases as clinical Tx stage, 60 cases missing clinical T staging data, 490 cases as clinical N0 stage, 373 cases as clinical N1 stage, 311 cases as clinical N2 stage, 86 cases as clinical Nx stage, 64 cases missing clinical N staging data, 156 cases with mesorectal fascia invasion, 223 cases with extraintestinal blood vessels invasion. The distance from lower margin of tumor to anal margin of 1 324 patients was 50(range, 40-60)mm. (2) Neoadjuvant therapy. Of the 1 761 patients, 873 patients underwent neoadjuvant therapy, including 17 cases receiving radiotherapy alone, 155 cases receiving chemotherapy alone, 43 cases receiving short-course simultaneous chemoradiotherapy, 26 cases receiving short-course simultaneous chemoradiotherapy and delayed surgery, 1 case receiving contact radiotherapy, 277 cases receiving long-course simultaneous chemoradiotherapy, 9 cases receiving other treatments, and 345 cases missing neoadjuvant therapy data. (3) Postoperative examinations. Of the 1 761 patients, 1 584 cases achieved R 0 resection, 23 cases achieved R 1 resection, 1 case achieved R 2 resection, and there were 153 cases missing surgical margin data. The tumor diameter, number of lymph nodes harvest and positive rate of intravascular tumor thrombus were 30(range, 20-45)cm, 13(range, 10-17) and 20.794%(330/1 587) in 1 761 patients. There were 1 647 patients with circumferential margin records, which showed positive in 51 cases, and the minimum distance from deep part of tumor to circumferential margin was 5(rang, 3-13)mm in 1 647 patients. There were 547 cases with distal margin records, which showed positive in 4 cases, and the distance from lower margin of tumor to distal margin was 20(10-25)mm in 547 cases. There were 1 698 patients with specimen integrity records, which showed intact specimen in 1 436 cases, fair specimen in 233 cases, poor specimen in 8 cases, unevaluated specimen in 21 cases, and there were 20 cases with rectal tube perforation. Of the 1 761 patients, cases as pathological T0 stage, Tis stage, T1 stage, T2 stage, T3 stage, T4 stage was 103, 23, 145, 515, 712, 179, respectively, and there were 4 cases of pathology that could not be evaluated and 80 cases missing pathological T staging data. Of the 1 761 patients, cases as pathological N0 stage, N1a stage, N1b stage, N1c stage, N2a stage, N2b stage was 1 117, 189, 133, 66, 109, 68, respectively, and there were 79 cases missing pathological N staging data. Of the 1 761 patients, there were 79 cases with distant metastasis, 1 591 cases without distant metastasis, and 91 cases without data of tumor metastasis. Of the 873 patients undergoing neoadjuvant therapy, there were 405 patients with tumor regression grade records including 105 cases as grade 1, 142 cases as grade 2, 91 cases as grade 3, 43 cases as grade 4, 24 cases as grade 5. Conclusions:In China, the quality of surgical specimens of taTME for rectal cancer is good with low positive rate of resection margin. It is recommended that using a formatted postoperative pathological report for good quality control of pathological report of surgical specimen.