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CC BY 4.0 · Journal of Digestive Endoscopy
DOI: 10.1055/s-0046-1817824
News and Views

Endoscopic Submucosal Dissection versus Surgery in the Resection of Early Rectal Cancer: Does the Knife Triumph over the Scalpel?

Authors

  • Nilanjan Kar

    1   Department of Gastroenterology, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, India

  • Sukanya Thakur

    1   Department of Gastroenterology, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, India

  • Vaneet Jearth

    1   Department of Gastroenterology, Post Graduate Institute of Medical Education and Research (PGIMER), Chandigarh, India
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Abstract

Colorectal cancer is a major global public health concern since it is the second most prevalent cause of cancer-related mortality worldwide. Early rectal neoplasia requires treatment strategies that ensure oncologic safety while preserving rectal function and quality of life. Transanal minimally invasive surgery (TAMIS) has traditionally served as a standard local excision technique, whereas endoscopic submucosal dissection (ESD) has emerged as a less invasive alternative capable of achieving en bloc resection of large, non-pedunculated rectal lesions. In this news and views, we will discuss the recently published DSETAMIS trial, which compares ESD and TAMIS for early rectal cancer.


Keywords

ESD - TAMIS - early rectal cancer - DSETAMIS trial

Colorectal cancer is a major global public health concern since it is the second most prevalent cause of cancer-related mortality worldwide.[1] The complexity of the pelvic anatomy, the necessity for radical surgery, and the intensity of multimodal treatments such as chemoradiotherapy are the primary factors contributing to the significant morbidity and need for permanent stomas in the management of rectal cancer.[2] Organ-preserving local excision in early-stage disease can alleviate the burden of such therapies that may negatively impact quality of life, besides reducing the associated mortality rate by 50%.[3]

In Western countries, early-stage rectal cancer is defined as lesions that are confined to the bowel wall, with invasion limited to the submucosa in T1 and the muscularis propria in T2 and no lymph node involvement (N0) or distant metastases (M0).[2] According to the Japanese classification, early carcinomas are categorized as Tis and T1. In early rectal cancer, local resection treatment options encompass three forms of transanal endoscopic surgery (TES): transanal endoscopic microsurgery (TEM), transanal endoscopic operations (TEO), and transanal minimally invasive surgery (TAMIS).[4] Surgically, TEO is an advancement of TEM with comparable outcomes at a lower cost. Furthermore, TAMIS is a feasible and less expensive alternative to TEM. Additionally, endoscopic resection techniques include endoscopic mucosal resection (EMR), underwater EMR, and endoscopic submucosal dissection (ESD). ESD offers a higher rate of en bloc resection, regardless of tumor size, as compared with EMR.[5] Although both endoscopic and minimally invasive surgical options have been demonstrated to be effective in the management of early rectal cancers, it is crucial to compare ESD and TAMIS to discuss the available options with the patient when expertise for both is available. The ongoing debate has been based exclusively on low-level evidence derived from retrospective observational studies.

The recently published DSETAMIS trial is the first randomized controlled trial (RCT) to compare TAMIS and ESD for a primary indication of early rectal neoplasms.[6] This noninferiority trial involved 73 patients with nonpedunculated early rectal neoplasia greater than 20 mm and ≤cT1N0, located between 3 and 14 cm from the external anal margin, with circumferential involvement ≤50%. Patients were randomized to undergo either ESD or TAMIS, with the aim of assessing local recurrence as the primary outcome at 12 months. Baseline characteristics were comparable across both groups. The authors selected a 10% noninferiority margin. All TAMIS operations relied on general anesthesia and endotracheal intubation, while ESD was conducted with deep sedation with spontaneous respiration in 16 cases (37.2%) and general anesthesia with endotracheal intubation in 27 cases (62.8%).

Two patients showed recurrence in the TAMIS arm within first 6 months with no recurrence observed in the ESD arm in intention-to-treat and per protocol analysis, the 12-month recurrence risk difference was −6.7% (90% confidence interval [CI]: −14.2 to 0.8) and −8.3% (90% CI: −17.6 to 0.9) showing ESD to be noninferior to TAMIS. In patients with local recurrence, one patient underwent endoscopic management and the other one required revision TAMIS. High-grade dysplasia was found in most patients, while pathological assessment showed adenocarcinoma in only 10 cases. In terms of secondary outcomes, the per-protocol analysis indicated significantly higher rates of R0 and curative resections in the ESD group. TAMIS was not feasible in 6 patients (18.2%), 3 of these patients underwent conventional transanal excision and the other 3 were successfully rescued with ESD. None of ESD procedures required conversion to another technique. The duration of hospital stay was reduced with ESD (1 day compared with 2 days; p < 0.001). Estimates of delayed complications were nearly halved in the ESD group, although not statistically significant (risk difference, –13.4%; 95% CI, –33.8 to 7.1; p = 0.2). Two cases of delayed hemorrhage in the TAMIS group required urgent endoscopic intervention, whereas none occurred after ESD. Ultimately, the cost analysis results indicated that ESD was significantly less expensive, with reductions of 83.1% in the intention-to-treat analysis and 103.1% in the per-protocol analysis. The procedure time favored TAMIS in this study (110 vs. 140 minutes; p = 0.02).

Commentary

The authors merit recognition for conducting a randomized trial that compares ESD and TAMIS, both of which are established techniques for treating early rectal neoplasms. The meta-analysis, which previously compared both modalities, included evidence from retrospective studies and found no significant differences in R0, recurrence, and complication rates.[7] The lesion characteristics in this study were favorable for TAMIS, as they were located within 3 to 14 cm from the anal verge and exhibited less than 50% circumferential involvement. However, ESD demonstrated superior performance in nearly all aspects, except for procedure duration, despite the larger tumor size observed in the ESD group post-randomization. The procedure duration did not include the time required for room setup and patient preparation time, which are anticipated to be longer for an operating theater compared with an endoscopy suite. The study also highlighted the higher acceptance rate of endoscopic techniques over surgical ones among patients. Three patients initially assigned to the TAMIS arm decided to switch to ESD, considering it to be a less invasive option, whereas no patients in the ESD arm requested a change. In the study, 18 eligible patients (not included in the analysis) selected ESD for the same reason, while only 4 patients chose TAMIS, regarding it as a more comprehensive approach. TAMIS, which permits full-thickness rectal wall resection, may appear more thorough than ESD in terms of deep margins; however, endoscopic intermuscular dissection, a recently reported modification of ESD, lowers the dissection plane into the intermuscular space and may counteract this theoretical drawback.[8] Additionally, ESD provides more accurate visual diagnosis in real time. There are no restrictions based on size (>5 cm, >50% of circumference) or location (lower rectum near dental line, upper rectum near rectosigmoid junction) and no detrimental effect on salvage surgery if needed. Salvage total mesorectal excision (TME) after TAMIS has potential for poorer oncological outcomes.

Although it was the first of its kind and a well-conducted randomized trial, it possessed several inherent methodological limitations. The predetermined inferiority margin for this study was 10%, which was obviously higher given that the expected local recurrence rate is relatively low (2.5%). This margin allows a strategy to be considered noninferior even if its recurrence rate is significantly higher than the expected recurrence.[9] [10] Keeping the margins wide resulted in a small sample size, and with very rare event (recurrence), the observed lack of recurrence in the ESD arm had low statistical significance. Another RCT (TRIASSIC trial) published as a conference abstract randomized 198 participants with nonpedunculated rectal lesions to ESD or TAMIS, applying a stricter noninferiority margin of 6%.[11] ESD outperformed TAMIS with no recurrences in the ESD arm and 6 recurrences in the TAMIS arm, representing a −6.4% risk difference (95% CI: −11.3 to −1.4).

The present study's sample size is inadequate for adjusting for operator experience, location, or lesion size. Late recurrences in early rectal neoplasia are well documented beyond 2 to 3 years.[12] The study demonstrates only short-term equivalence as the median duration of follow-up was 15 months but could not comment on long-term oncologic safety. Functional outcomes, including incontinence and quality of life, were not reported but often considered crucial for any rectal interventions. In comparison, the Dutch TRIASSIC study showed that fecal incontinence, medication use, and the overall Colorectal Functional Outcome (COREFO) score were all better in the ESD arm.[11]

The authors did not assess the utility of real-time optical diagnosis in conjunction with endoscopy. Surgeons depend on magnetic resonance imaging or endoscopic ultrasound. The outcomes of salvage TME after TAMIS were not addressed. Lastly, the study was performed at high-volume expert centers with operator experience of at least 10 TAMIS procedures and 30 ESD procedures, including 5 rectal ESD, which might compromise the generalizability of the results. ESD has a longer and steeper learning curve than TAMIS, hence it should only be attempted at expert centers for optimal outcomes. TAMIS, in contrast to ESD, facilitates full-thickness resection, enabling the resection of lesions that penetrate deeper into the submucosa as well as those characterized by extensive fibrosis or scarring. Consequently, the selection of patients and the availability of local expertise are critical factors in determining the appropriate procedure. Limited evidence also suggests that the combined ESD–TAMIS approach has the potential to extract the best of both procedures when rectal lesions are not optimum for each procedure, such as low-lying lesions just above the dentate line with extensive fibrosis.[13]

Consequently, current evidence supports an ESD-first approach in carefully selected patients at experienced centers, while TAMIS should remain a valid option when depth of invasion is uncertain or surgical staging and salvage predictability are prioritized.



Conflict of Interest

None declared.


Address for correspondence

Vaneet Jearth, MD, DM, MRCP (SCE)
Department of Gastroenterology, PGIMER
Chandigarh 160012
India   

Publication History

Article published online:
23 February 2026

© 2026. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (https://creativecommons.org/licenses/by/4.0/)

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