Total Mesorectal Excision Versus Local Excision After Preoperative Chemoradiotherapy in Rectal Cancer With Lymph Node Metastasis: A Propensity Score-Matched Analysis

Rectal cancer approach strategies after neoadjuvant treatment - a systematic review and network meta-analysis

BACKGROUND AND AIMS

An increasing number of patients with rectal cancer who respond well to neoadjuvant chemoradiotherapy (nCRT) are being considered for organ preservation programs. However, due to the lack of high-level evidence, the survival outcomes of the organ preservation programs are still full of controversy and uncertainty.

METHODS

To assess the effects of total mesorectal excision (TME) surgery, watch-and-wait (W&W), and local excision (LE) on long-term outcomes after nCRT, we searched PubMed, Embase, and Web of Science for articles published between 1 January 2010, and 31 December 2023.

RESULTS

We found 7029 pieces of literature, of which 26 studies met the inclusion criteria, and recruited 2778 participants in the network meta-analysis. Risk of bias assessment showed that most included studies had a low risk of bias. Low-certainty evidence suggests that the TME group was significantly superior to all other interventions for the 2-year local regrowth rate. (W&W group [OR, 0.20; 95% CI, 0.12-0.35], LE group compared with TME group [3.00; 1.60-5.80]). There was no significant difference in the 2-year local regrowth rate between W&W and LE group (OR, 0.60; 95% CI, 0.32-1.20). There was high to moderate certainty evidence that at 3 years, the W&W group had a significant advantage in overall survival compared with the TME group (OR, 0.37; 95% CI, 0.09-0.95). After 5 years, no significant difference in overall survival was found between the 3 treatment modalities.

CONCLUSIONS

We concluded that TME achieved the most significant reduction in 2-year local regrowth rates. However, the W&W strategy and LE demonstrated noninferiority to TME in long-term survival outcomes.

Therapeutic strategies for ypT1 rectal cancer after neoadjuvant chemoradiotherapy: a retrospective cohort study

PURPOSE

The optimal treatment of ypT1 rectal cancer after neoadjuvant chemoradiotherapy (nCRT) remains controversial. This study aimed to determine whether local excision is non-inferior to radical surgery and whether adjuvant chemotherapy (ACT) would improve survival in patients with ypT1 rectal cancer after nCRT.

METHODS

We enrolled 1212 and 91 patients with ypT1 rectal cancer underwent nCRT followed by radical surgery from the SEER database (2004-2018) and the Zhejiang Cancer Hospital (ZJCH) (2010-2022), respectively. Another 62 patients underwent LE were also identified from SEER registries. Propensity score matching was performed to balance baseline characteristics between patients in different treatment groups.

RESULTS

Regional nodal metastasis was histopathologically detected in 257 patients (20.7%) within the SEER cohort, showing a significant association with poor cancer-specific survival (CSS) and overall survival (OS). Consistent findings were also observed in the ZJCH cohort. After 1:1 propensity score matching (60 pairs), no significant differences were observed between the extended resection and local excision groups in CSS (hazard ratio [HR] 0.88, P = 0.785) and OS (HR 0.81, P = 0.450). Patients with regional nodal metastases were more likely to receive ACT, while no apparent survival benefit was observed with additional ACT after PSM adjusting (187 pairs). Notwithstanding, for individuals younger than 50 years, ACT might provide a survival benefit in CSS (HR 0.25, P = 0.033) and OS (HR 0.30, P = 0.022).

CONCLUSION

Although patients with ypT1 rectal cancer have a non-negligible risk for nodal metastasis, oncologic outcomes of local excision following nCRT seem to be comparable to radical surgery. ACT could not effectively improve prognosis in patients with ypT1 tumors, except for those younger than 50 years of age.

Long-term efficacy of transanal local excision versus total mesorectal excision after neoadjuvant treatment for rectal cancer: A meta-analysis

AIM

The purpose of this meta-analysis is to compare the long-term efficacy of transanal local excision (TLE) versus total mesorectal excision (TME) following neoadjuvant therapy for rectal cancer.

METHOD

The Web of Science, Pubmed, Medline, Embase, and the Cochrane Library were systematically searched for correlational research. The Newcastle-Ottawa Scale and the Cochrane risk of bias tool were used to assess the quality of cohort studies (CSs) and randomized controlled trials (RCTs), respectively. Statistically analyzed using RevMan5.4.

RESULT

A total of 13 studies, including 3 randomized controlled trials (RCTs) and 10 cohort studies (CSs), involving 1402 patients, were included in the analysis. Of these, 570 patients (40.66%) underwent TLE, while 832 patients (59.34%) underwent TME. In the meta-analysis of CSs, no significant difference was observed between the TLE group and TME group regarding 5-year overall survival (OS) and 5-year disease-free survival (DFS) (P > 0.05). However, the TLE group had a higher rates of local recurrence (LR) [risk ratio (RR) = 1.93, 95%CI (1.18, 3.14), P = 0.008] and a lower rates of 5-years local recurrence-free survival (LRFS) [hazard ratio (HR) = 2.79, 95%CI (1.04, 7.50), P = 0.04] compared to the TME group. In the meta-analysis of RCTs, there was no significant difference observed between the TLE group and TME group in terms of LR, 5-year OS, 5-year DFS, and 5-year disease-specific survival (P > 0.05).

CONCLUSION

After undergoing neoadjuvant therapy, TLE may provide comparable 5-year OS and DFS to TME for rectal cancer. However, neoadjuvant therapy followed by TLE may has a higher LR and lower 5-year LRFS compared to neoadjuvant therapy followed by TME, so patients should be carefully selected. Neoadjuvant therapy followed by TLE may be a suitable option for patients who prioritize postoperative quality of life. However, the effectiveness of this approach requires further research to draw a definitive conclusion.

Oncologic comparison between nonradical management and total mesorectal excision in good responders after chemoradiotherapy in patients with mid-to-low rectal cancer

Purpose

This study was performed to compare the oncologic outcomes between nonradical management and total mesorectal excision in good responders after chemoradiotherapy.

Methods

We analyzed 75 patients, who underwent 14 watch-and-wait, 30 local excision, and 31 total mesorectal excision, in ycT0-1N0M0 based on magnetic resonance imaging after chemoradiotherapy for advanced mid-to-low rectal cancer in 3 referral hospitals. The nonradical management group underwent surveillance with additional sigmoidoscopy and rectal magnetic resonance imaging every 3-6 months within the first 2 years.

Results

Nonradical management group had more low-lying tumors (P < 0.001) and less lymph node metastasis based on magnetic resonance imaging (P = 0.004). However, cT stage, ycT, and ycN stage were not different between the 2 groups. With a median follow-up period of 64.7 months, the 5-year locoregional failure rate was higher in the nonradical management group than in the total mesorectal excision group (16.7% vs. 0%, P = 0.013). However, the 5-year overall survival and disease-free survival rates of the nonradical management and total mesorectal excision groups were not different (95.2% vs. 93.5%, P = 0.467; 76.4% vs. 83.6%, P = 0.665; respectively).

Conclusion

This study shows that nonradical management for ycT0-1N0 mid-to-low rectal cancer may be an alternative treatment to total mesorectal excision under proper surveillance and management for oncologic events.

Local excision in mid-to-low rectal cancer patients who revealed clinically total or near-total regression after preoperative chemoradiotherapy; a proposed trial

BACKGROUND

Preoperative chemoradiotherapy (pre-CRT) followed by total mesorectal excision (TME) is currently a standard therapy for locally advanced mid-to-low rectal cancer. Less aggressive, organ-preserving option such as local excision (LE) or watchful wait can alternatively be used for patients who respond well to pre-CRT. High-resolution rectal magnetic resonance imaging (MRI) is one of the most useful methods to assess pre-CRT response, and the MERCURY group has shown that the MR tumor regression grade (mrTRG) correlated with the pathologic TRG. The aim of this study is to compare postoperative complication and oncologic outcomes between LE and TME in mid-to-low rectal cancer patients whose tumors are mrTRG grade 1 (radiological complete remission) or 2 (predominant fibrosis; near-complete remission) after pre-CRT.

METHODS

A prospective, double-arm, randomized, open-labeled, single center, clinical trial will be conducted in patients with mid-to-low rectal cancer whose tumors are mrTRG 1/2 after pre-CRT at the Asan Medical Center, Seoul, Korea, after approval from the Institution Review Board. Patient medical records will be de-identified using a serial number to protect personal information. Inclusion criteria will include rectal adenocarcinoma with an inferior border < 8 cm from the anal verge, mrTRG 1/2, age > 20, and provision of informed consent. Postoperative complications will be assessed by Clavien-Dindo Classification Grade. Oncologic and functional outcomes will be collected and risk factors related to these outcomes will be investigated.

DISCUSSION

We believed that the rate of postoperative complication of LE will be comparable to that of TME in mid-to-low advanced rectal cancer patients with a favorable response after pre-CRT.

TRIAL REGISTRATION

KCT0002579 ( https://cris.nih.go.kr ) Dec-2017.

A systematic review and meta-analysis of pT2 rectal cancer spread and recurrence pattern: Implications for target design in radiation therapy for organ preservation

BACKGROUND

There are no guidelines on clinical target volume (CTV) delineation for cT2 rectal cancer treated with organ preservation.

MATERIALS AND METHODS

A systematic review and meta-analysis were performed to determine the extent of distal mesorectal (DMS) and distal intramural spread (DIS), the risk of lateral lymph node (LLN) metastases in pT2 tumours, and regional recurrence pattern after organ preservation.

RESULTS

The rate of DMS > 1 cm was 1.9% (95% CI: 0.4-5.4%), maximum extent: 1.3 cm. The rate of DIS > 0.5 cm was 4.7% (95% CI: 1.3-11.5%), maximum extent: 0.8 cm. The rate of LLN metastases was 8.2% (95% CI: 6.7-9.9%) for tumours below or at peritoneal reflexion and 0% for higher tumours. Regional nodal recurrences alone were recorded in 1.0% (95% CI: 0.5-1.7%) of patients after watch-and-wait and in 2.1% (95% CI: 1.2-3.4%) after preoperative radiotherapy and local excision. Thus, the following rules for CTV delineation are proposed: caudal border 1.5 cm from the tumour to account for DMS or 1 cm to account for DIS, whichever is more caudal; cranial border at S2/S3 interspace; inclusion of LLN for tumours at or below peritoneal reflexion. A planning study was performed in eight patients to compare dose-volume parameters obtained using these rules to that obtained using current guidelines for advanced cancers. The proposed rules led to a mean 18% relative reduction of planning target volume, which resulted in better sparing of organs-at-risk.

CONCLUSION

This meta-analysis suggests a smaller CTV for cT2 tumours than the current guidelines designed for advanced cancers.