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Updated: Sep 24, 2025
Robot-assisted Total Mesorectal Excision and Lateral Pelvic Lymph Node Dissection for Locally Advanced Middle-low Rectal Cancer
Published on: February 12, 2022
Involvement of tissue changes induced by neoadjuvant treatment in total mesorectal excision (TME): novel suggestions
Jin Cheon Kim1, Seong Ho Park2, Jihun Kim3
1Department of Surgery, University of Ulsan College of Medicine and Asan Medical Center, Seoul, 05505, Republic of Korea. jckim@amc.seoul.kr.
Background:
Few studies to date have investigated morphological changes after neoadjuvant treatment (NAT) and their implications in total mesorectal excision (TME). This study was primarily designed to evaluate whether tissue changes associated with NAT affected the quality of TME and additionally to suggest a more objective method evaluating TME quality.
Methods:
This study enrolled 1322 consecutive patients who underwent curative robot-assisted surgery for rectal cancer. Patients who did and did not receive NAT were subjected to propensity-score matching, yielding 402 patients in each group.
Results:
NAT independently reduced complete achievement of TME [odds ratio (OR) = 2.056, p = 0.017]. Intraoperative evaluation identified seven tissue changes significantly associated with NAT, including tumor perforation, mucin pool, necrosis, fibrosis, fat degeneration, and rectal or perirectal edema NAT (p < 0.001-0.05). Tumor perforation (OR = 5.299, p = 0.001) and mucin pool (OR = 14.053, p = 0.002) were independently associated with inappropriate (near-complete + incomplete) TME. Complete TME resulted in significantly reduced local recurrence (4.3% vs 15.3%, p = 0.003) and increased 5-year DFS rate (80.6% vs 67.6%, p = 0.047) compared with inappropriate one. By contrast, two tiers of complete and near-complete TMEs vs incomplete TME did not. Notably, among patients with complete TME, those who received NAT had a lower 5-year DFS than those who did not (77.8% vs 83.3%, p = 0.048).
Conclusions:
NAT-associated tissue changes, somewhat interrupting complete TME, may provide unsolved clue to the relative inability of NAT to improve overall survival. The conventional three-tier grading of TME seems to be simplified into two tiers as complete and inappropriate.
Insights
Neoadjuvant treatment (NAT) for rectal cancer can alter tissues, potentially impacting the quality of total mesorectal excision (TME). Complete TME is crucial for better outcomes, but NAT may complicate its achievement.
Area of Science:
- Colorectal surgery
- Surgical oncology
- Rectal cancer research
Background:
- Limited research exists on morphological changes post-neoadjuvant treatment (NAT) and their impact on total mesorectal excision (TME) quality.
- This study addresses the effect of NAT-induced tissue changes on TME quality and proposes an objective assessment method.
Purpose of the Study:
- To evaluate the impact of NAT-associated tissue alterations on the quality of TME.
- To propose a more objective method for assessing TME quality in rectal cancer surgery.
Main Methods:
- 1322 rectal cancer patients undergoing robot-assisted surgery were analyzed.
- Propensity-score matching created comparable groups of 402 patients who received NAT versus those who did not.
Main Results:
- NAT independently decreased complete TME achievement (OR=2.056, p=0.017).
- Tissue changes like tumor perforation and mucin pool were linked to incomplete TME.
- Complete TME correlated with reduced local recurrence and improved 5-year disease-free survival (DFS), though NAT in complete TME cases showed lower 5-year DFS.
Conclusions:
- NAT-induced tissue changes can compromise complete TME quality, potentially explaining NAT's limited impact on overall survival.
- A simplified TME grading system of 'complete' versus 'inappropriate' is suggested over the traditional three-tier system.
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