Transanal Local Excision Research Articles

Win Statistics in Observational Cancer Research: Integrating Clinical and Quality-of-Life Outcomes.

Background: Quality-of-life metrics are increasingly important for oncological patients alongside traditional endpoints like mortality and disease progression. Statistical tools such as Win Ratio, Win Odds, and Net Benefit prioritize clinically significant outcomes using composite endpoints. In randomized trials, Win Statistics provide fair comparisons between treatment and control groups. However, their use in observational studies is complicated by confounding variables. Propensity score (PS) matching mitigates confounding variables but may reduce the sample size, affecting the power of win statistics analyses. Alternatively, PS matching can stratify samples, preserving the sample size. This study aims to assess the long-term impact of these methods on decision making, particularly in colorectal cancer patients. Methods: A motivating example involves a cohort of patients from the ReSARCh observational study (2016-2021) with locally advanced adenocarcinoma of the rectum, situated up to 12 cm from the anal verge. These patients underwent either a watch-and-wait approach (WW) or trans-anal local excision (LE). Win statistics compared the effects of WW and LE on a composite outcome (overall survival, recurrence, presence of ostomy, and rectum excision). For matched win statistics, we used robust inference techniques proposed by Matsouaka et al. (2022), and for stratified win statistics, we applied the method proposed by Dong et al. (2018). A simulation study assessed the coverage probability of matched and stratified win statistics in balanced and unbalanced groups, calculating how often the confidence intervals included the true values of WR, NB, and WO across 1000 simulations. Results: The results suggest a better efficacy of the LE approach when considering efficacy outcomes alone (WR: 0.47 (0.01 to 1.14); NB: -0.16 (-0.34 to 0.02); and WO: 0.73 (0.5 to 1.05)). However, when QoL outcomes are included in the analyses, the estimates are closer to 1 (WR: 0.87 (0.06 to 2.06); WO: 0.93 (0.61 to 1.4)) and to 0 (NB: -0.04 (-0.25 to 0.17)), indicating a negative impact of the treatment effect of LE regarding the presence of ostomy and the excision of the rectum. Moreover, based on the simulation study, our findings underscore the superior performance of matched compared to stratified win statistics in terms of coverage probability (matched WR: 97% vs. stratified WR: 33.3% in a high-imbalance setting; matched WR: 98% vs. stratified WR: 34.4% in a medium-imbalance setting; and matched WR: 99.2% vs. stratified WR: 37.4% in a low-imbalance setting). Conclusions: In conclusion, our study sheds light on the interpretation of the results of win statistics in terms of statistical significance, providing insights into the application of pairwise comparison in observational settings, promoting its use to improve outcomes for cancer patients.

Rectal Sparing Approach after preoperative Radio- and/or Chemo-therapy (ReSARCh): a prospective, multicenter, observational study.

Rectal-sparing approaches for patients with rectal cancer who achieved a complete or major response following neoadjuvant therapy constitute a paradigm of a potential shift in the management of patients with rectal cancer; however, their role remains controversial. The aim of this study was to investigate the feasibility of rectal-sparing approaches to preserve the rectum without impairing the outcomes. This prospective, multicenter, observational study investigated the outcomes of patients with clinical stage II-III mid-low rectal adenocarcinoma treated with any neoadjuvant therapy, and either transanal local excision or watch-and-wait approach, based on tumor response (major or complete) and patient/surgeon choice. The primary endpoint of the study was rectum preservation at a minimum follow-up of 2 years. Secondary endpoints were overall, disease-free, local and distant recurrence-free, and stoma-free survival at 3 years. Of the 178 patients enrolled in 16 centers, 112 (62.9%) were managed with local excision and 66 (37.1%) with watch-and-wait. At a median (interquartile range) follow-up of 36.1 (30.6-45.6) months, the rectum was preserved in 144 (80.9%) patients. The 3-year rectum-sparing, overall survival, disease-free survival, local recurrence-free survival, and distant recurrence-free survival was 80.6% (95% CI 73.9-85.8), 97.6% (95% CI 93.6-99.1), 90.0% (95% CI 84.3-93.7), 94.7% (95% CI 90.1-97.2), and 94.6% (95% CI 89.9-97.2), respectively. The 3-year stoma-free survival was 95.0% (95% CI 89.5-97.6). The 3-year regrowth-free survival in the watch-and-wait group was 71.8% (95% CI 59.9-81.2). In rectal cancer patients with major or complete clinical response after neoadjuvant therapy, the rectum can be preserved in about 80% of cases, without compromising the outcomes.

Local Excision for Early-Stage Rectal Adenocarcinomas.

Although total mesorectal excision (TME) remains the standard of care for rectal cancer, including early-stage T1/T2 rectal adenocarcinoma, local excision may be warranted for these early-stage tumors in a select group of patients who may decline surgery or may be nonoptimal surgical candidates. Operative approaches for transanal local excision include transanal endoscopic microsurgery or transanal minimally invasive surgery for tumors <4 cm, occupying <40% of the rectal circumference and <10 cm from the dentate line. The use of preoperative chemoradiation therapy may help to downstage tumors and allow for more limited resections, and chemoradiation may also be employed postoperatively. Local excision approaches appear to result in improved quality of life compared with TME, but limited resections may also compromise survival rates compared with TME. Multidisciplinary management and shared decision-making can allow for the desired patient outcomes.

Lokalno radikalno lečenje patoloških lezija rektuma minimalno invazivnim hirurškim pristupima

Introduction: The most common pathological changes treated in the rectum are neoplastic polyps (villous, tubular, and tubulovillous adenomas) and rectal adenocarcinomas. Until now, precancerous lesions of the type of neoplastic polyps have been treated with a local approach, and patients with advanced cancers have been operated on with a radical surgical intervention, either classically or laparoscopically. Aim: In this paper, we will show the advantages and disadvantages of certain local surgical approaches to pathological changes in the rectum. Material and methods: Our research analyzed two groups of patients. In the first group, patients with pathological lesions of the rectum were treated with local transanal excision (TAE), and the second group of patients were treated with the newly introduced technique of transanal minimally invasive surgery (TAMIS). In the period from September 2021 to March 2023. at the CHC Zemun in Surgery Clinic, a total of 12 patients were operated on with the TAMIS procedure and 15 patients with the TAE technique for various pathological changes in the rectum. In all patients, the changes were localized in the rectum from 5 to 15 cm from the anocutaneous line in the TAMIS group and from 0 to 6 cm in the TAE group. Pathological changes could not be resected by endoscopic polypectomy. Results: The average duration of the operations was longer in the TAMIS group and amounted to 45 minutes, while the operations lasted an average of 20 minutes in the TAE group. During the surgical procedure, mucosectomy is most often performed, followed by resection of the full thickness of the rectal wall, and resection of the rectal wall with part of the mesorectal tissue was performed the least frequently in both analyzed groups. In 3 patients we had preparation fragmentation, and in 1 case we had positive margins by histopathological postoperative analysis in the TAMIS group. In the TAE group, we had one patient with preparation fragmentation and a positive margin. Patients with a positive margin in both the TAE and TAMIS groups belonged to villous adenomas with a high degree of dysplasia. The final HP finding in both groups most often spoke in favor of tubulovillous adenoma with a low to medium degree of dysplasia. In both groups, we had 2 cases of early intramucosal carcinoma T1 stage. Discussion: The postoperative period of hospitalization is shorter in TAE compared to TAMIS (1.3 days compared to 1.8 days). We had no serious postoperative complications in any of the observed groups. In one case, we had postoperative bleeding, which was treated with endoscopic hemostasis. Such low percentages of postoperative complications, even in our small series of patients, justify the introduction of the TAMIS procedure into daily practice for the surgical treatment of large endoscopically unresectable rectal polyps of high rectal localization. Conclusion: Based on our work and the available literature, we can conclude that radical local resections of TAE and TAMIS are a viable alternative to surgical radical rectal resection in polypoid changes and early T1 rectal cancers with less morbidity, faster recovery, and lower treatment costs. These techniques are safe, effective, and reproducible.

Surgical Techniques for Transanal Local Excision for Early Rectal Cancer

Surgical Techniques for Transanal Local Excision for Early Rectal Cancer

Endoscopic and trans-anal local excision vs. radical resection in the treatment of early rectal cancer: A systematic review and network meta-analysis.

The management of early-stage rectal cancer in clinical practice is controversial. The aim of this network meta-analysis was to compare oncological and postoperative outcomes for T1T2N0M0 rectal cancers managed with local excision in comparison to conventional radical resection. A systematic review of Medline, Embase and Cochrane electronic databases was performed. Relevant studies were selected using PRISMA guidelines. The primary outcomes measured were 5-year local recurrence and overall survival. Secondary outcomes included rates of postoperative complication, 30-day mortality, positive margin and permanent stoma formation. Three randomized controlled trials and 27 observational studies contributed 8570 patients for analysis. Radical resection was associated with reduced 5-year local recurrence in comparison to local excision. This was statistically significant in comparison to trans-anal local excision (odds ratio (OR) 0.23; 95% confidence interval 0.16-0.30) and favourable in comparison to endoscopic techniques (OR 0.40; 95% confidence interval 0.13-1.23) although this did not reach clinical significance. Positive margin rates were lowest for radical resection. However, 30-day mortality rates, perioperative complications and permanent stoma rates all favoured local excision with no statistically significant difference between endoscopic and trans-anal techniques. Radical resection of early rectal cancer is associated with the lowest 5-year local recurrence rates and the lowest rate of positive margins. However, this must be balanced with its higher 30-day mortality and complication rates as well as the increased risk of permanent stoma. The emerging potential role of neoadjuvant therapy prior to local resection, and the heterogeneity of its use, as an alternative treatment for early rectal cancer further complicates the treatment paradigm and adds to controversy in this field.

Optimisation of Organ Preservation treatment strategies in patients with rectal cancer with a good clinical response after neoadjuvant (chemo)radiotherapy: Additional contact X-ray brachytherapy versus eXtending the observation period and local excision (OPAXX) — protocol for two multicentre, parallel, single-arm, phase II studies

IntroductionStandard treatment for patients with intermediate or locally advanced rectal cancer is (chemo)radiotherapy followed by total mesorectal excision (TME) surgery. In recent years, organ preservation aiming at improving quality of...

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

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. 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. 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). 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.

Practice Patterns for Organ Preservation in US Patients With Rectal Cancer, 2006-2020

In March 2023, the National Comprehensive Cancer Network endorsed watch and wait for those with complete clinical response to total neoadjuvant therapy. Neoadjuvant therapy is highly efficacious, so this recommendation may have broad implications, but the current trends in organ preservation in the US are unknown. To describe organ preservation trends among patients with rectal cancer in the US from 2006 to 2020. This retrospective, observational case series included adults (aged ≥18 years) with rectal adenocarcinoma managed with curative intent from 2006 to 2020 in the National Cancer Database. The year of treatment was the primary exposure. The type of therapy was chemotherapy, radiation, or surgery (proctectomy, transanal local excision, no tumor resection). The timing of therapy was classified as neoadjuvant or adjuvant. The primary outcome was the absolute annual proportion of organ preservation after radical treatment, defined as chemotherapy and/or radiation without tumor resection, proctectomy, or transanal local excision. A secondary analysis examined complete pathologic responses among eligible patients. Of the 175 545 patients included, the mean (SD) age was 63 (13) years, 39.7% were female, 17.4% had clinical stage I disease, 24.7% had stage IIA to IIC disease, 32.1% had stage IIIA to IIIC disease, and 25.7% had unknown stage. The absolute annual proportion of organ preservation increased by 9.8 percentage points (from 18.4% in 2006 to 28.2% in 2020; P < .001). From 2006 to 2020, the absolute rate of organ preservation increased by 13.0 percentage points for patients with stage IIA to IIC disease (19.5% to 32.5%), 12.9 percentage points for patients with stage IIIA to IIC disease (16.2% to 29.1%), and 10.1 percentage points for unknown stages (16.5% to 26.6%; all P < .001). Conversely, patients with stage I disease experienced a 6.1-percentage point absolute decline in organ preservation (from 26.4% in 2006 to 20.3% in 2020; P < .001). The annual rate of transanal local excisions decreased for all stages. In the subgroup of 80 607 eligible patients, the proportion of complete pathologic responses increased from 6.5% in 2006 to 18.8% in 2020 (P < .001). This case series shows that rectal cancer is increasingly being managed medically, especially among patients whose treatment historically relied on proctectomy. Given the National Comprehensive Cancer Network endorsement of watch and wait, the increasing trends in organ preservation, and the nearly 3-fold increase in complete pathologic responses, international professional societies should urgently develop multidisciplinary core outcome sets and care quality indicators to ensure high-quality rectal cancer research and care delivery accounting for organ preservation.

Transanal local excision versus intersphincteric resection for low rectal cancer with stage ypT0-1ycN0 after neoadjuvant chemoradiotherapy: an inverse probability weighting analysis for oncological and functional outcomes.

This study aimed to compare the efficacy of local excision (LE) and intersphincteric resection (ISR) in patients with locally advanced rectal cancer who achieved a significant or complete pathological response following neoadjuvant chemoradiotherapy. We performed a retrospective analysis of data from patients with stage ypT0-1ycN0 low rectal cancer after neoadjuvant chemoradiotherapy who underwent LE or ISR between June 2016 and June 2021. Baseline characteristics, short-term outcomes, long-term oncological outcomes, and functional outcomes, were compared between the two groups. To reduce the selection bias, inverse probability of treatment weighting (IPTW) was performed. This study included 106 patients (LE group: n = 51, ISR group: n = 55). There were significant differences in baseline characteristics between the two groups (P < 0.05). After IPTW, there were almost no significant differences in baseline data between the two groups. The LE group showed less postoperative complications and better function outcomes compared to the ISR group. The LE group had significantly lower rates of complications (13.7% vs. 36.4%, P = 0.014). There were no significant differences between the two groups in terms of long-term oncological outcomes. For patients with locally advanced low rectal cancer achieving significant or complete pathological response after neoadjuvant therapy, both LE and ISR present comparable oncological outcomes. Yet, LE seems to show more advantages in terms of postoperative complications and functional outcomes. These findings offer important insights for surgical decision-making, emphasizing the necessity to consider both oncological and functional outcomes in selecting the optimal surgical approach.

778 New Intervention: Transanal Local Excision of Rectal Lesions with CMR Versius Robotic Surgical System

Abstract Introduction The Versius robotic surgical system (CMR) is a modular robotic platform. Since its launch in clinical practice in 2019 for General Surgical and Gynaecological procedures it has rapidly expanded into other clinical specialties. We describe its implementation and the world's first series of its use for trans-anal resection of significant rectal lesions. Method The optimum bedside unit set-up and port placement was determined in an exploratory study using dry and wet-lab models prior to clinical implementation. The early intervention panel at NHS Lothian were consulted prior to introducing the technique into clinical practice. The case series of patients undergoing robotic Trans-Anal Minimally Invasive Surgery (rTAMIS) were prospectively identified and data collected retrospectively. Results A total of 12 patients were included in this case series. Data was collected from cases over a 6-month period from December 2021 to June 2022. 8 patients underwent robotic TAMIS using the Versius platform. 2 cases were converted to laparoscopic TAMIS due to external arm clashes. The average length of stay in hospital was 1 day (range 0-3). There was only one Clavien-Dindo grade II morbidity. Conclusions The Versius surgical system is a safe and feasible alternative to TEMS and TAMIS. The technique allows access to the rectum with the advantages of enhanced optics and wristed instruments. We have produced a blueprint for optimised bedside unit positioning and port placement enabling resection of anterior, lateral, and posterior rectal lesions without further patient position changes. Further studies are needed for accurate outcome and cost comparisons to TEMS and TAMIS.

Lymph Node Metastasis in Extraperitoneal Rectal Cancer After Neoadjuvant Therapy: An Unsolved Problem?

Thanks to the promising benefits obtained in terms of quality of life, there has been growing interest in organ-sparing approaches after neoadjuvant chemoradiotherapy (nCRT) in patients with locally advanced rectal cancer, mainly represented by transanal local excision and watch-and-wait. The main mandatory criterion is complete lymph nodal response (pN0). However, considering the reduced specificity of current radiological means in identifying one-to-one correspondence between clinical and pathological staging, the problem of underestimating lymph nodal involvement remains unsolved. The aim of this study was to identify the true percentage of patients eligible for conservative surgery and possible predictive factors. Data for 59 patients with rectal cancer treated with nCRT followed by total mesorectal excision were analyzed. Patients with metastatic tumors and tumors treated with up-front surgery were excluded. Our primary endpoint was the pathological lymph nodal response rate after neoadjuvant chemoradiotherapy. The secondary endpoint was to identify predictive factors for lymph nodal response. The percentage of patients with pN0 was 62.71%, while in 37.28%, an organ-sparing approach would have not been oncologically correct. Parameters associated with pN0 were lower tumor size (T0-T2) (p=0.013) and lower grading (<G3) (p=0.06). Parameters associated with poorer disease-free survival were pN+ (p=0.019), higher lymph node ratio (p=0.001), and higher stage (p=0.038). Organ-sparing approaches may be a promising option in patients with extraperitoneal rectal cancerthat respond to nCRT. Nevertheless, it is essential to consider the limit of lymph node metastases to ensure oncological safety and, especially in cases with advanced tumors, total mesorectal excision should be the approach of choice.

Predictors and outcomes of positive surgical margins after local excision of clinical T1 rectal cancer: A National Cancer Database analysis

BackgroundTransanal local excision and the use of specialized platforms has become increasingly popular for early-stage rectal cancer. Predictors and outcomes of positive resection margins following transanal local excision for early-stage rectal cancer have yet to be explored. MethodsThis was a retrospective analysis of the National Cancer Database of all patients with clinical nonmetastatic node negative T1 rectal adenocarcinoma who underwent transanal local excision from 2004 to 2017. Patients with positive surgical margins were compared to those with negative resection margins to determine factors associated with predictors and outcomes of positive surgical margins after transanal local excision. The main outcome measure was overall survival. ResultsOf 318,548 patients with rectal adenocarcinoma in the National Cancer Database, 9,078 (2.8%) met the inclusion criteria. The positive surgical margins rate was 7.4%. Predictors of positive surgical margins were older age (odds ratio, 1.03; P < .001), higher Charlson comorbidity index (odds ratio, 1.24; P = .004), poorly differentiated carcinomas (odds ratio, 1.89; P < .001), mucinous (odds ratio, 2.36; P = .003) and signet-ring cell carcinomas (odds ratio, 4.7; P = .048). Independent predictors of reduced survival were older age (hazard ratio, 1.062; P < .001), male sex (hazard ratio, 1.214; P = .011), Charlson comorbidity index 3 (hazard ratio, 1.94; P < .001), pathologic T2 (hazard ratio, 1.27; P = .036) and T3 stages (hazard ratio, 1.77; P = .006), poorly differentiated carcinomas (hazard ratio, 1.47; P = .008), and positive surgical margins (hazard ratio, 1.374; P = .018). The positive surgical margins group's median overall survival was significantly shorter (88 vs 159.3 months, P < .001). ConclusionPositive surgical margins after transanal local excision for early-stage node-negative rectal cancer adversely affects prognosis. Older male patients with higher Charlson comorbidity index scores and poorly differentiated mucinous or signet cell histology tumors are at risk for positive surgical margins. Patient selection according to these suggested criteria may help avoid positive surgical margins.

Transanal local excision for mucosal prolapse syndrome.

A 46-year-old male visited our hospital with blood stool and constipation. Colonoscopy revealed a broad-based protruded lesion in the rectum.The endoscopic ultrasonography showed the lesion invaded the submucosa, and the boundary between the local and intrinsic muscular layer was not clear. Transanal local excision was conducted, the pathology showed a rare case of mucosal prolapse syndrome merging chronic suppurative inflammation.

Complete resection of a giant tumor in the ultralow rectum by a combination of transanal local excision and endoscopic submucosal dissection.

Complete resection of a giant tumor in the ultralow rectum by a combination of transanal local excision and endoscopic submucosal dissection.

Local full-thickness excision for sessile adenoma and cT1-2 rectal cancer: long-term oncological outcome

PurposeWe analyzed all patients who underwent local transanal surgery at our institution to determine oncological outcomes and perioperative risk.MethodsIn 1997, we developed a prospective protocol for rectal tumors: transanal local full-thickness excision was considered curative in patients with benign adenoma and early cancers. In this analysis, 404 patients were included. To analyze survival, only those patients exposed to the risk of dying for at least 5 years were considered for the study.ResultsThe final pathological analysis revealed that 262 (64.8%) patients had benign lesions, whereas 142 had malignant lesions. Postoperative complications were recorded in 12.6%. At the median time of 21 months, 14% of the adenomas and 12% of cancers had recurred, half of which were surgically resected. The overall 5-year survival rate was 94%.ConclusionWith similar outcomes and significantly lower morbidity, we found local surgery to be an adequate alternative to radical surgery in selected cases of early rectal cancer.

Radical vs. Local Excision in Rectal Carcinoma T1N0M0: Recurrence and Mortality Rates.

Local transanal excision of early rectal carcinoma is an appealing treatment because of its low morbidity rates and better functional results than radical resection. However, this treatment approach is controversial due to its association with local recurrence when compared to the latter. This review aims to compare the local recurrence and mortality rates of local vs. radical excision in patients with T1N0M0 rectal carcinoma, based on data in the literature in the last 20 years. A PubMed, Cochrane, and Google Scholar search of published literature in the last 20 years was performed. A total of 12 studies were identified. Three were prospective, one was a population-based propensity matching study, one was a nationwide cohort study, one was a meta-analysis, and the remaining studies were retrospective/observational.The mean local recurrence rate within five years from the studies selected for local excision (LE: 12.8%) was nearly double that of radical excision (RAD: 5.0%). The five-year mean survival rate for both LE and RAD groups from the studies selected was 86%, which was equal for both groups. The main predictors of poor outcomes were older age and the presence of two or more comorbid conditions.There is a consensus amongst studies that LE is associated with inferior oncological outcomes such as postoperative complications and recurrence when compared to RAD. The higher local recurrence rates in LE are attributed to occult lymph node disease and inadequate adjunctive therapy due to suboptimal staging. There is no difference in the five-year survival rate when compared to RAD. A longer follow-up period is needed to determine whether the survival rates diverge after five years.

Completion Total Mesorectal Excision After Transanal Local Excision of Early Rectal Cancer: A Systematic Review and Meta-analysis.

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.

Research Perspective on Completion Total Mesorectal Excision After Transanal Local Excision of Early Rectal Cancer: A Systematic Review and Meta-analysis.

Funding/Support: None reported. Financial Disclosures: None reported. Correspondence: Tarik Sammour, F.R.A.C.S, Ph.D., Royal Adelaide Hospital, Port Rd Adelaide, South Australia 5000, Australia. E-mail: [email protected]

The importance of MRI for rectal cancer evaluation

Magnetic resonance imaging (MRI) has gained increasing importance in the management of rectal cancer over the last two decades. The role of MRI in patients with rectal cancer has expanded beyond the tumor-node-metastasis (TNM) system in both staging and restaging scenarios and has contributed to identifying “high” and “low” risk features that can be used to tailor and personalize patient treatment; for instance, selecting the patients for neoadjuvant chemoradiation (NCRT) before the total mesorectal excision (TME) surgery based on risk of recurrence. Among those features, the status of the circumferential resection margin (CRM), extramural vascular invasion (EMVI), and tumor deposits (TD) have stood out. Moreover, MRI also has played a role in surgical planning, especially when the tumor is located in the low rectum, when the relationship between tumor and the anal canal is important to choose the best surgical approach, and in cases of locally advanced or recurrent tumors invading adjacent pelvic organs that may require more complex surgeries such as pelvic exenteration. As approaches using organ preservation emerge, including transanal local excision and “watch-and-wait”, MRI may help in the patient selection for those treatments, follow up, and detection of tumor regrowth. Additionally, potential MRI-based prognostic and predictive biomarkers, such as quantitative and semi-quantitative metrics derived from functional sequences like diffusion-weighted imaging (DWI) and dynamic contrast-enhanced (DCE), and radiomics, are under investigation. This review provides an overview of the current role of MRI in rectal cancer in staging and restaging and highlights the main areas under investigation and future perspectives.