Volume-Outcome Relationships in Total Mesorectal Excision Quality and Grading: A National Cancer Database Study

Total mesorectal excision (TME) is the surgical standard for mid-to-low rectal cancer, and the Commission on Cancer Standard 5.7 requires documentation of TME grade. The aim of our study was to describe national variation in TME grading and quality.

This was a multicenter retrospective cohort of 5033 patients within the National Cancer Database who underwent TME for rectal adenocarcinoma in 2022, the first year TME quality is available. The exploratory outcomes were TME reporting and completeness by institution volume, assessed by quartiles and by the Leapfrog Group's standard of 16 proctectomies/year, and the associations of TME grades with surgical approach, lymph node yield, and surgical margins.

There were significant differences in likelihood of TME reporting (p < 0.001) and in TME grades (p < 0.001) by facility volume quartile. Meeting the Leapfrog minimum of 16 annual proctectomies was associated with a higher likelihood of reporting TME grade (p = 0.02) but not with more complete TME grades (p = 0.68). Robotic-assisted approaches had the highest rate of complete TME among surgical approaches (p < 0.001) and lower rates of conversion to open than did laparoscopic approaches (4.6% vs 14.6%, p < 0.001). Complete TME was more likely to have at least 12 lymph nodes (p = 0.001), no residual tumor (p < 0.001), and negative circumferential resection margins (p < 0.001) than nearly complete and incomplete TME.

High-volume institutions were more likely to report TME grades and achieve complete TME, which was associated with higher rates of adequate lymph node yield and negative margins. Robotic-assisted approaches were associated with the highest rates of complete TME grades.