Local excision of early rectal cancer: A multi-centre experience of transanal endoscopic microsurgery from the United Kingdom.

Local excision for early rectal cancer has gained widespread interest. Currently available imaging modalities have low sensitivity to detect locoregional disease, which may result in understaging and a high risk of recurrence after local excision. The purpose of this work was to study the morbidity, mortality, and long-term oncologic outcomes in a select cohort of patients undergoing salvage surgery for local recurrence after local excision of early rectal cancer. A retrospective review of patient charts was used to determine patterns of disease recurrence and outcomes as a single-institution case series. The study was conducted at a tertiary care cancer center. The study cohort included patients with early rectal cancer treated by local excision who then developed local recurrence for which a multimodal salvage surgery with curative intent was performed between 1997 and 2013 at our center. Log rank tests were used to measure overall and disease-free survival. Twenty-seven patients were identified, with a mean age of 66 ± 12 years. The median time to recurrence was 54 weeks (range, 7-326 weeks). Recurrent disease was luminal in 23 patients, regional (involving both mesorectal and pelvic lymph nodes) in 6 patients, and both luminal and nodal in 2 patients. For salvage surgery, neoadjuvant chemoradiation was used in 12 patients (44%), and radiation alone was used in 1 patient. Sphincter-preserving surgery was performed in 9 patients (33%). R0 resection was achieved in 25 patients (93%). Four patients received intraoperative radiation therapy. Five-year overall survival was 50% (95% CI, 30%-74%), and re-recurrence-free survival was 47% (95% CI, 25%-68%). This study was limited by its retrospective nature, small patient cohort, referral bias, and selection bias. Even in highly selected patients who undergo surgery for local recurrence after transanal excision of early stage rectal cancer, oncologic outcomes are poor.

BackgroundAvailable platforms for local excision (LE) of early rectal cancer are rigid or flexible [trans‑anal minimally invasive surgery (TAMIS)]. We systematically searched the literature to compare outcomes between platforms.MethodsPRISMA-compliant search of PubMed and Scopus databases until September 2022 was undertaken in this random-effect meta-analysis. Statistical heterogeneity was assessed using I2 statistic. Studies comparing TAMIS versus rigid platforms for LE for early rectal cancer were included. Main outcome measures were intraoperative and short-term postoperative outcomes and specimen quality.Results7 studies were published between 2015 and 2022, including 931 patients (423 females); 402 underwent TAMIS and 529 underwent LE with rigid platforms. Techniques were similar for operative time (WMD 11.1, 95%CI − 2.6 to 25, p = 0.11), percentage of defect closure (OR 0.7, 95%CI 0.06–8.22, p = 0.78), and peritoneal violation (OR 0.41, 95%CI 0.12–1.43, p = 0.16). Rigid platforms had higher rates of short-term complications (19.1% vs 14.2, OR 1.6, 95%CI 1.07–2.4, p = 0.02), although no significant differences were seen for major complications (OR 1.41, 95%CI 0.61–3.23, p = 0.41). Patients in the rigid platforms group were 3-times more likely to be re-admitted within 30 days compared to the TAMIS group (OR 3.1, 95%CI 1.07–9.4, p = 0.03). Rates of positive resection margins (rigid platforms: 7.6% vs TAMIS: 9.34%, OR 0.81, 95%CI 0.42–1.55, p = 0.53) and specimen fragmentation (rigid platforms: 3.3% vs TAMIS: 4.4%, OR 0.74, 95%CI 0.33–1.64, p = 0.46) were similar between the groups. Salvage surgery was required in 5.5% of rigid platform patients and 6.2% of TAMIS patients (OR 0.8, 95%CI 0.4–1.8, p = 0.7).ConclusionTAMIS or rigid platforms for LE seem to have similar operative outcomes and specimen quality. The TAMIS group demonstrated lower readmission and overall complication rates but did not significantly differ for major complications. The choice of platform should be based on availability, cost, and surgeon’s preference.

The impact of transanal local excision (TAE) of early rectal cancer (ERC) on subsequent completion rectal resection (CRR) for unfavorable histology or margin involvement is unclear. The aim of this study was to provide a comprehensive review of the literature on the impact of TAE on CRR in patients without neoadjuvant chemoradiotherapy (CRT). We performed a systematic review of the literature up to March 2020. Medline and Cochrane libraries were searched for studies reporting outcomes of CRR after TAE for ERC. We excluded patients who had neoadjuvant CRT and endoscopic local excision. Surgical, functional, pathological and oncological outcomes were assessed. The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines were followed. Sixteen studies involving 353 patients were included. Pathology following TAE was as follows T0 = 2 (0.5%); T1 = 154 (44.7%); T2 = 142 (41.2%); T3 = 43 (12.5%); Tx = 3 (0.8%); T not reported = 9. Fifty-three percent were > T1. Abdominoperineal resection (APR) was performed in 80 (23.2%) patients. Postoperative major morbidity and mortality occurred in 22 (11.4%) and 3 (1.1%), patients, respectively. An incomplete mesorectal fascia resulting in defects of the mesorectum was reported in 30 (24.6%) cases. Thirteen (12%) patients developed recurrence: 8 (3.1%) local, 19 (7.3%) distant, 4 (1.5%) local and distant. The 5-year cancer-specific survival was 92%. Only 1 study assessed anal function reporting no continence disorders in 11 patients. In the meta-analysis, CRR after TAE showed an increased APR rate (OR 5.25; 95% CI 1.27-21.8; p 0.020) and incomplete mesorectum rate (OR 3.48; 95% CI 1.32-9.19; p 0.010) compared to primary total mesorectal excision (TME). Two case matched studies reported no difference in recurrence rate and disease free survival respectively. The data are incomplete and of low quality. There was a tendency towards an increased risk of APR and poor specimen quality. It is necessary to improve the accuracy of preoperative staging of malignant rectal tumors in patients scheduled for TAE.

Introduction The role of local excision for early rectal cancer continues to be a topic of debate due to high local recurrence rates. The quality of local excision is an important factor determining risk of local recurrence. Small T1 (Sm1 and Sm2) tumours can be adequately treated with trans-anal excision using specialised techniques such as trans-anal endoscopic microsurgery (TEM) or trans-anal endoscopic operation (TEO). Current practice dictates radical surgery (RS) for all other rectal tumours to achieve acceptable oncological outcomes. Method A retrospective analysis of prospectively kept data from a single centre case series of patients treated with TEM for early rectal cancer. We analysed data for patients who had rectal preservation without subsequent RS, and were followed up with regular clinical examination, blood tests, CT chest/abdomen/pelvis and MRI rectum. All local excisions were approved by the local MDT and performed by 2 trained consultant colorectal surgeons. Results Sixty eight patients underwent TEM for early rectal cancer between June 2009 and August 2013, 25 patients went on to have RS and 1 TEM was converted intra-operatively to RS. Forty two patients (61.8%), 31 males (73.8%), were followed up with rectal preservation. The mean age was 74 years (S. D =/- 9.8) and ASA grades of patients: ASA I 2.4%; ASA II 35.7%; ASA III 54.8%; and ASA IV 7.1%. The median height of tumour was 7cm (range 1–15), operative time was 90 min (range 30 – 320), and in all cases blood loss was minimal. Median length of stay was 2 days (range 1–17). Median tumour size was 20mm (range 2–50) and the pathological stage was T1 in 20/42 (45.2%) (Sm1 5/20[25%], Sm2 8/20[40%], Sm3 7/20[35%]), T2 in 17/42 (40.5%) and T3 in 3/42 (7.1%) patients. Two patients (4.8%) had no residual tumour following neo-adjuvant therapy/polypectomy. The TEM specimen contained lymph nodes in 6/42 cases (14.3%), positive in 2/42 (4.8%). The overall local recurrence rate was 9.5% (4/42 unfit or unwilling for RS, 2 with involved margins). The local recurrence rate with clear margins was 5.3%. Recurrence rate for T0, T1, T2 and T3 disease was 0% (0/2), 0% (0/19), 6.2% (1/16) and 33.3% (1/3) respectively when excluding recurrences with positive margins. The median length of follow up 17 months (range 3–60) and rectal cancer specific mortality was 2.4% (1 patient unfit for radical surgery with T3 disease). Conclusion This case series demonstrates a very low recurrence rate in contrast to most of the published series. We believe the technique and quality of surgery is an important factor contributing to local recurrence following local resection. We propose that further studies should be considered for identifying additional patients in whom rectal preservation can be safely offered. Disclosure of interest None Declared.

Total mesorectal excision (TME) has been firmly established as the standard of care for rectal cancer. Its principles include precise anatomic resection of the rectum and its mesentery to ensure negative circumferential resection margins and central vascular ligation to ensure removal of all relevant regional lymph nodes. While TME is variably combined with radiation and chemotherapy for locally advanced tumors, surgery alone is indicated for stage I tumors. For these early tumors, expert surgeons can achieve local control rates of approximately 95% and 5-year overall survival rates in excess of 90%. Given these excellent outcomes, why meddle? But surprisingly, as reported in the article that accompanies this editorial, Stitzenberg et al demonstrate that the rates of non-TME, local resection for stage I rectal cancer have risen between 1998 and 2010: for T1 cancers, from 39.8% to 62%, and for T2 cancers from 12.2 to 21.4%. These findings show that the trend identified in a previous study from 2007 has continued unabated. That study, like the present one, utilized the National Cancer Data Base to document a rise in local excision rates between 1989 and 2003 from 26.6 to 43.7% for T1 and from 5.8% to 16.8% for T2 cancers. It also showed a near tripling of the risk of local recurrence following local therapy compared with radical surgery, and decrease in disease-specific but not overall survival. Thus, given the excellent results achievable with TME, can the widespread use of local excision be justified? Local excision of early rectal cancer gained acceptance as a treatment option after Morson et al’s 1977 publication of the St Mark’s Hospital (London, United Kingdom) 25-year experience with the technique. The authors, noting a local recurrence rate of 3% following excision with negative resection margins, 14% following excision with doubtful margins, and 36% following excision with positive margins, emphasized the importance of thorough histological examination of the excised specimen, which they considered to be an excisional biopsy. Incomplete resection, transmural extension, and poor histologic differentiation were all considered to be indications for radical resection. Enthusiasm for local excision was dampened with publication of a series of sobering retrospective case series from major centers showing local recurrence rates of 15% to 29% for T1% and 26% to 47% for T2 cancers, only a minority of which received chemoradiotherapy. Equally alarming was the realization that salvage therapy after failed local resection is far from ideal. Recurrent cancers invariably present at a more advanced stage than the original tumor—hardly a surprising result given that locoregional recurrence occurs either in the full-thickness resection bed or in undetected or inadequately treated metastatic disease in the mesorectum. Patients with recurrent cancers also generally require chemoradiotherapy before radical resection, often require multivisceral resections, and frequently end up with permanent stomas. Yet, despite this aggressive treatment, local recurrence is fatal in almost 50% of patients—individuals who would have had a high likelihood of cure had they undergone radical resection when they first presented. There are several reasons why local excision might lead to treatment failure. First, despite the advantages of transanal endoscopic microsurgery (TEM) over conventional transanal excision, both approaches create a raw surface in the mesorectum where tumor cells can at least theoretically implant. More importantly, because the mesorectum is left largely or entirely untouched in local excision, success of the approach is critically dependent on proper patient selection. Undiagnosed metastases in regional lymph nodes are not treated and serve as the nidus for eventual locoregional recurrence. Unfortunately, even in the most skilled hands, imaging to detect nodal disease is imperfect: meta-analyses show sensitivities and specificities for detecting metastatic lymph nodes of 73.2% and 75.8% for endorectal ultrasound (ERUS) and 77% and 71% for magnetic resonance imaging (MRI). One is left with surrogate markers, the most useful of which is T stage: nodal positivity is approximately 10% to 13% in T1% and 17% to 22% in T2 cancers. But other factors play a role. Tumor grade and the presence of angiolymphatic invasion are important. For T1 cancers, deep invasion into the submucosal layer is a predictor of nodal positivity. One report suggests that female sex significantly increases the risk of nodal metastases. Tumor budding and poor differentiation at the invasive front appear to be particularly important predictors of nodal disease in early rectal cancers, and numerous additional histopathological factors have been suggested. The best evidence supporting local excision of early rectal cancers emerged from Cancer and Leukemia Group B (CALGB) 8984, a multi-institutional prospective trial. In this study, T1 cancers were treated by local excision alone, and T2 by local excision with adjuvant chemoradiotherapy. At a median follow-up of 7 years, local recurrence rates were 8% for T1% and 18% for T2 tumors; corresponding disease-free survival rates were 75% and 64%, respectively. One critical weakness of this study is that it is not based on an intention-totreat analysis. Excised tumors underwent pathologic review that lead to exclusion of almost one third of patients who met initial eligibility JOURNAL OF CLINICAL ONCOLOGY E D I T O R I A L VOLUME 31 NUMBER 34 DECEMBER 1 2013

This study aimed to determine clinical outcomes of local excision for early rectal cancer from a University Hospital in Thailand. We performed a retrospective review of 22 consecutive patients undergoing local excision for early rectal cancer (clinical and radiological T1/T2) from 2005-2010 at the Faculty of Medicine, Siriraj Hospital, Mahidol University, Bangkok. Data were collected from patients' medical records, including demographic and clinical characteristics, pathological report and surgical outcomes. This study included 10 males and 12 females, with average age of 68 years. Nineteen patients (86%) underwent transanal excision and the others had trans-sacral excision. Median operative time was 45 minutes. Postoperative complications occurred in 2 patients (9%); 1 fecal fistula and 1 wound infection following trans-sacral excision. There was no 30-day postoperative mortality. Median hospital stay was 5 days. Pathological reports revealed T1 lesion in 12 cases (55%), T2 lesion in 8 cases (36%) and T3 lesion in 2 cases (9%). Eight patients received additional treatment; one re-do transanal excision, two proctectomies, and five adjuvant chemoradiation. During the median follow-up period of 25 months, local recurrence was detected in 4 patients (18%); two cases of T2 lesions with close or positive margins, and two cases of T3 lesions. Three patients with local recurrence underwent salvage abdominoperineal resection. No local recurrence was found in T1/T2 lesions with free surgical margins. Local excision is a feasible and acceptable alternative to radical resection only in early rectal cancer with free resection margins and favorable histopathology.

Radical surgery of rectal cancer is associated with significant morbidity, and some patients with low-lying lesions must accept a permanent colostomy. Several studies have suggested satisfactory tumor control after local excision of early rectal cancer. The purpose of this study was to compare recurrence and survival rates after treating early rectal cancers with local excision and radical surgery. One hundred eight patients with T1 and T2 rectal adenocarcinomas treated by transanal excision were compared with 153 patients with T1N0 and T2N0 rectal adenocarcinomas treated with radical surgery. Neither group received adjuvant chemoradiation. Mean follow-up time was 4.4 years after local excision and 4.8 years after radical surgery. The estimated five-year local recurrence rate was 28 percent (18 percent for T1 tumors and 47 percent for T2 tumors) after local excision and 4 percent (none for T1 tumors and 6 percent for T2 tumors) after radical surgery. Overall recurrence was also higher after local excision (21 percent for T1 tumors and 47 percent for T2 tumors) than after radical surgery (9 percent for T1 tumors and 16 percent for T2 tumors). Twenty-four of 27 patients with recurrence after local excision underwent salvage surgery. The estimated five-year overall survival rate was 69 percent after local excision (72 percent for T1 tumors and 65 percent after T2 tumors) and 82 percent after radical surgery (80 percent for T1 tumors and 81 percent for T2 tumors). Differences in survival rate between local excision and radical surgery were statistically significant in patients with T2 tumors. Local excision of early rectal cancer carries a high risk of local recurrence. Salvage surgery is possible in most patients with local recurrence, but may be effective only in patients with T1 tumors. When compared with radical surgery, local excision may compromise overall survival in patients with T2 rectal cancers.

Local excision for early rectal cancer has low morbidity and good functional results. Its use is limited by the inability to assess regional lymph nodes and by the uncertainty of oncologic outcome. We conducted a retrospective chart review of all patients who underwent local excision of early rectal cancer in two colorectal units between 1995 and 2007. The retrieved and analyzed data were patient age and gender, tumor size, tumor distance from the anal verge, tumor differentiation, and additional treatment. There were 42 patients with T1 rectal cancer: 24 underwent transanal endoscopic microsurgery and 18 had a transanal excision. The surgical margins were free of tumor in 39 patients (93%), they were involved by tumor in one (2%) and margin status was unclear in two (5%). Seven patients (16%) had postoperative complications. There was no postoperative mortality. The mean hospital stay was 67 h. Thirty-nine patients (93%) were followed up for 57 months (mean). Two patients had local recurrence, at 7 and 41 months post-surgery. They had a tumor that invaded into the lower third of the submucosa, sm3. Both received chemoradiotherapy, and underwent an abdominoperineal resection and a low anterior resection. One of them died of metastatic disease 13 months later and the other is alive with no evidence of disease. Another two patients had salvage low anterior resection, one for suspected local recurrence and one for lymphovascular invasion: the specimens were tumor free. Six patients died of unrelated causes. Local excision of early rectal cancer is a feasible and acceptable alternative to radical resection. It has low complication and recurrence rates and a short postoperative hospital stay.

Completion total mesorectal excision is recommended when local excision of early rectal cancers demonstrates high-risk histopathological features. Concerns regarding the quality of completion resections and the impact on oncological safety remain unanswered. This study aims to summarize and analyze the outcomes associated with completion surgery and undertake a comparative analysis with primary rectal resections. Data sources included PubMed, Cochrane library, MEDLINE, and Embase databases up to April 2021. All studies reporting any outcome of completion surgery after transanal local excision of an early rectal cancer were selected. Case reports, studies of benign lesions, and studies using flexible endoscopic techniques were not included. The intervention was completion total mesorectal excision after transanal local excision of early rectal cancers. Primary outcome measures included histopathological and long-term oncological outcomes of completion total mesorectal excision. Secondary outcome measures included short-term perioperative outcomes. Twenty-three studies including 646 patients met the eligibility criteria, and 8 studies were included in the meta-analyses. Patients undergoing completion surgery have longer operative times (standardized mean difference, 0.49; 95% CI, 0.23-0.75; p = 0.0002) and higher intraoperative blood loss (standardized mean difference, 0.25; 95% CI, 0.01-0.5; p = 0.04) compared with primary resections, but perioperative morbidity is comparable (risk ratio, 1.26; 95% CI, 0.98-1.62; p = 0.08). Completion surgery is associated with higher rates of incomplete mesorectal specimens (risk ratio, 3.06; 95% CI, 1.41-6.62; p = 0.005) and lower lymph node yields (standardized mean difference, -0.26; 95% CI, -0.47 to 0.06; p = 0.01). Comparative analysis on long-term outcomes is limited, but no evidence of inferior recurrence or survival rates is found. Only small retrospective cohort and case-control studies are published on this topic, with considerable heterogeneity limiting the effectiveness of meta-analysis. This review provides the strongest evidence to date that completion surgery is associated with an inferior histopathological grade of the mesorectum and finds insufficient long-term results to satisfy concerns regarding oncological safety. International collaborative research is required to demonstrate noninferiority. CRD42021245101.

Outcomes after Local Excision for Rectal Cancer

The goal of treatment for early stage rectal cancer is to optimize oncologic control while minimizing the long-term impact of treatment on quality of life. The standard of care treatment for most stage I and II rectal cancers is radical surgery alone, specifically total mesorectal excision (TME). For early rectal cancers, this procedure is usually curative but can have a substantial impact on quality of life, including the possibility of permanent colostomy and the potential for short and long-term bowel, bladder, and sexual dysfunction. Given the morbidity associated with radical surgery, alternative approaches to management of early rectal cancer have been explored, including local excision (LE) via transanal excision (TAE) or transanal endoscopic microsurgery (TEM) and transanal minimally invasive surgery (TAMIS). Compared to the gold standard of radical surgery, local procedures for strictly selected early rectal cancers should lead to identical oncological results and even better outcomes regarding morbidity, mortality, and quality of life.

BackgroundThe risks of local recurrence and treatment‐related morbidity need to be balanced after local excision of early rectal cancer. The aim of this meta‐analysis was to determine oncological outcomes after local excision of pT1–2 rectal cancer followed by no additional treatment (NAT), completion total mesorectal excision (cTME) or adjuvant (chemo)radiotherapy (aCRT).MethodsA systematic search was conducted in PubMed, Embase and the Cochrane Library. The primary outcome was local recurrence. Statistical analysis included calculation of the weighted average of proportions.ResultsSome 73 studies comprising 4674 patients were included in the analysis. Sixty‐two evaluated NAT, 13 cTME and 28 aCRT. The local recurrence rate for NAT among low‐risk pT1 tumours was 6·7 (95 per cent c.i. 4·8 to 9·3) per cent. There were no local recurrences of low‐risk pT1 tumours after cTME or aCRT. The local recurrence rate for high‐risk pT1 tumours was 13·6 (8·0 to 22·0) per cent for local excision only, 4·1 (1·7 to 9·4) per cent for cTME and 3·9 (2·0 to 7·5) per cent for aCRT. Local recurrence rates for pT2 tumours were 28·9 (22·3 to 36·4) per cent with NAT, 4 (1 to 13) per cent after cTME and 14·7 (11·2 to 19·0) per cent after aCRT.ConclusionThere is a substantial risk of local recurrence in patients who receive no additional treatment after local excision, especially those with high‐risk pT1 and pT2 rectal cancer. The lowest recurrence risk is provided by cTME; aCRT has outcomes comparable to those of cTME for high‐risk pT1 tumours, but shows a higher risk for pT2 tumours.

Total mesorectal excision (TME) is the gold standard in rectal cancer, if curation is intended. Transanal endoscopic microsurgery (TEM) is a much safer technique and seems to have comparable survival in early rectal cancer. The impact of both procedures on quality of life has never been compared. In this study we compared quality of life after TEM and TME. Fifty-four patients underwent TEM for a T1 carcinoma. Only patients without known locoregional or distant recurrences were included, resulting in 36 eligible patients in whom quality of life after TEM was studied. The questionnaires used included the EuroQol EQ-5D, EQ-VAS, EORTC QLQ-C30 and EORTC QLQ-CR38. The results were compared with a sex-and age-matched sample of T+N0 rectal cancer patients who had undergone sphincter saving surgery by TME and a sex- and age matched community-based sample of healthy persons. Thirty-one patients after TEM returned completed questionnaires (overall response rate 86%). Quality of life was compared with 31 TME patients and 31 healthy controls. From the patients' and social perspective quality of life did not differ between the three groups. Compared with TEM, significant defecation problems were seen after TME (P < 0.05). A trend towards better sexual functioning after TEM, compared with TME, was seen, especially in male patients, although it did not reach statistical significance. Transanal endoscopic microsurgery and TME do not seem to differ in quality of life postoperatively, but defecation disorders are more frequently encountered after TME. This difference could play a role in the choice of surgical therapy in (early) rectal cancer. Further prospective studies are needed to confirm our conclusions.

BackgroundTransanal minimally invasive surgery (TAMIS) is an advanced technique for excision of early rectal cancers. Robotic TAMIS (r-TAMIS) has been introduced as technical improvement and potential alternative to total mesorectal excision (TME) in early rectal cancers and in frail patients. This study reports the perioperative and short-term oncological outcomes of r-TAMIS for local excision of early-stage rectal cancers.MethodsRetrospective analysis of a prospectively collected r-TAMIS database (July 2021–July 2023). Demographics, clinicopathological features, short-term outcomes, recurrences, and survival were investigated.ResultsTwenty patients were included. Median age and body mass index were 69.5 (62.0–77.7) years and 31.0 (21.0–36.5) kg/m2. Male sex was prevalent (n = 12, 60.0%). ASA III accounted for 66.7%. Median distance from anal verge was 7.5 (5.0–11.7) cm. Median operation time was 90.0 (60.0–112.5) minutes. Blood loss was minimal. There were no conversions. Median postoperative stay was 2.0 (1.0–3.0) days. Minor and major complication rates were 25.0% and 0%, respectively. Seventeen (85.0%) patients had an adenocarcinoma whilst three patients had an adenoma. R0 rate was 90.0%. Most tumours were pT1 (55.0%), followed by pT2 (25.0%). One patient (5.0%) had a pT3 tumour. Specimen and tumour maximal median diameter were 51.0 (41.0–62.0) mm and 21.5 (17.2–42.0) mm, respectively. Median specimen area was 193.1 (134.3–323.3) cm2. Median follow-up was 15.5 (10.0–24.0) months. One patient developed local recurrence (5.0%).Conclusionsr-TAMIS, with strict postoperative surveillance, is a safe and feasible approach for local excision of early rectal cancer and may have a role in surgically unfit and elderly patients who refuse or cannot undergo TME surgery. Future prospective multicentre large-scale studies are needed to report the long-term oncological outcomes.

3622 Background: Colorectal cancer is the third common cancer worldwide. Radical excision (RE) as total mesorectal excision for rectal cancer carries a higher risk of mortality and morbidity, while local excision (LE) could decrease these postoperative risks. However, the long-term oncologic outcomes of LE are still debatable. We aim to study the effect of LE versus RE in T1 and T2 rectal cancer. Methods: We conducted a systematic review and meta-analysis. We searched PubMed and CENTRAL databases, using an optimized search-strategy from inception until 15 June 2021, without restriction on publication date or status. We included only cohort and randomized controlled trials (RCTs). Two authors independently screened the title, abstracts, and full-text manuscripts for inclusion and data extraction. All included trials contained at least one of the primary outcomes. We used RevMan 5.4 tool for data analysis. We calculated both hazards ratio (HR) and risk ratio (RR) for the 5-years survival analyses, with their 95% confidence intervals (CI). We assessed both clinical and statistical heterogeneity of the studies; I2 &gt;75% was considered highly heterogeneous. We used random effect model (REM). We used standardized mean difference (SMD) for hospitalization days. We conducted a subgroup analysis of patients with T1-only without adjuvant chemo/radiotherapy (CRT). Results: We retrieved from the search a total of 1243 reports. A total of 18 studies were included for final meta-analysis (4 RCTs and 14 retrospective cohorts). Nine studies were multi-central while ten were unicentral studies. We did not find any difference in risk ratio (RR) between overall survival (OVS) and disease-free survival (DFS). But there were higher HRs in OVS and DFS with LE as compared to RE. A higher recurrence rate was also seen with LE. Six studies showed absent 30-days postoperative mortality in both groups so we used peto-odds ratio. Postoperative mortality and morbidity were lower with LE rather than RE. Conclusions: LE for early stage rectal cancer has a higher risk of decreased 5-year OVS and DFS than RE, with higher local recurrence rate. However, LE is associated with lower early postoperative mortality, morbidity, and hospitalization days, as compared to RE. Patient selection is key to balance these risks for the optimal outcome. [Table: see text]