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

PURPOSE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Is preoperative hypoalbuminemia or hypoproteinemia a reliable marker for anastomotic leakage risk in patients undergoing elective colorectal surgery in an enhanced recovery after surgery (ERAS) program?

PURPOSE: Preoperative hypoalbuminemia has traditionally been used as a marker of nutritional status and is considered a significant risk factor for anastomotic leak (AL). METHODS: The Westmead Enhanced Recovery After Surgery (WERAS) prospectively collected database, consisting of 361 patients who underwent colorectal surgery with primary anastomosis, was interrogated. Preoperative serum albumin and protein levels (measured within 1 week of surgery) were plotted on receiver operating characteristic curves (ROC curves) and statistically analyzed for cutoff values, sensitivity, specificity, positive predictive values (PPV), and negative predictive values (NPV). RESULTS: The incidence of AL was 4.4% (16/361). Overall mortality was 1.4% (5/361), 6.3% (1/16) in the AL group, and 1.2% (4/345) in the no AL group. The median preoperative albumin and protein level in the AL group were 39 g/L and 75 g/L, respectively. The median preoperative albumin and protein level in the no AL group were 38 g/L and 74 g/L, respectively. The Mann-Whitney U test showed no statistically significant difference in albumin levels (p = 0.4457) nor protein levels (p = 0.6245) in the AL and no AL groups. ROC curves demonstrated that preoperative albumin and protein levels were not good predictors of anastomotic leak. Cutoff values for albumin (38 g/L) and protein (75 g/L) both had poor PPV for AL (4.8% and 3.8% respectively). CONCLUSION: In patients undergoing elective colorectal surgery as part of an ERAS program, preoperative serum albumin and protein levels are not reliable in predicting AL. This may be because of nutritional supplementation provided as part of an ERAS program may correct nutritional deficits to protect against AL or that low albumin/protein is not as robust a marker of AL as previously reported.

Severe constipation causing ischaemic stercoral perforation of sigmoid colon.

Stercoral perforation is a rare but life-threatening condition that is increasingly being recognised as a sequelae of severe constipation. We present the case of a 45-year-old female who presented with stercoral perforation secondary to severe constipation related to adjuvant chemotherapy for colorectal cancer on a background of long-term antipsychotic medications. Chemotherapy-induced neutropaenia posed an additional treatment consideration in the management of sepsis associated with stercoral perforation. This case demonstrated that the morbidity and mortality from constipation especially in at risk patients cannot be underestimated.

Robotic-assisted versus laparoscopic rectal surgery in obese and morbidly obese patients: ACS-NSQIP analysis.

Laparoscopic rectal surgery within the confines of a narrow pelvis may be associated with a high rate of open conversion. In the obese and morbidly obese patient, the complexity of laparoscopic surgery increases substantially. Robotic technology is known to reduce the risk of conversion, but it is unclear if it can overcome the technical challenges associated with obesity. The ACS NSQIP database was used to identify obese patients who underwent elective laparoscopic or robotic-assisted rectal resection from 2015 to 2016. Obesity was defined as a body mass index (BMI) greater than or equal to 30 kg/m2. Morbid obesity was defined as a BMI greater than or equal to 35 kg/m2. The primary outcome was unplanned conversions to open. Other outcomes measures assessed included anastomotic leak, operative time, surgical site infections, length of hospital stay, readmissions and mortality. Statistical analyses were performed using SPSS 22.0 (IBM SPSS, USA). 1490 patients had robotic-assisted and 4967 patients had laparoscopic rectal resections between 2015 and 2016. Of those patients, 561 obese patients had robotic-assisted rectal resections and 1824 patients underwent laparoscopic rectal surgery. In the obese cohort, the rate of unplanned conversion to open in the robotic group was 14% compared to 24% in the laparoscopic group (P < 0.0001). Median operative time was significantly longer in the robotic group (248 min vs. 215 min, P < 0.0001). There was no difference in anastomotic leak or systemic sepsis between the laparoscopic and robotic rectal surgery groups. In morbidly obese patients (BMI ≥ 35 kg/m2), the rate of unplanned conversion to open in the robotic group was 19% compared to 26% in the laparoscopic group (P < 0.027). There was no difference in anastomotic leak, systemic sepsis or surgical site infection rates between robotic and laparoscopic rectal resection. Multivariate analysis showed that robotic-assisted surgery was associated with fewer unplanned conversions to open (OR 0.28, P < 0.0001). Robotic-assisted surgery is associated with a decreased risk of conversion to open in obese and morbidly obese patients when compared to conventional laparoscopic surgery. However, robotic surgery was associated with longer operative time and despite improvement in the rate of conversion to open, there was no difference in complications or length of stay. Our findings are limited by the retrospective non-randomised nature of the study, demographic differences between the two groups, and the likely difference in surgeon experience between the two groups. Large randomised controlled studies are needed to further explore the role of robotic rectal surgery in obese and morbidly obese patients.

A tale of two twists: mesentero-axial and organo-axial sigmoid volvulus.

INTRODUCTION: Sigmoid volvulus is a potentially devastating and life-threatening condition associated with sigmoid colon redundancy. Many of the classical radiological signs are considered to represent the two adjacent loops of bowel in a mesentero-axial volvulus. However, limited case reports and series have reported on an organo-axial subtype of sigmoid volvulus. This clinical entity is not widely understood. In this study, we assess the radiological and clinical features of mesentero-axial and organo-axial sigmoid volvulus. METHODS: After institutional board approval (CH62/6/2016-228), all computed tomography (CT) studies from 2011 to 2017 reported as sigmoid volvulus at a single institution were reviewed. The cases were reviewed by three radiologists retrospectively and the course of the bowel followed with a focus on assessing its rotational axis. In each case, the sigmoid volvulus was independently subclassified as mesentero-axial or organo-axial volvulus based on the axis of rotation of the volvulus. In addition, X-ray signs including disproportionate sigmoid dilatation, distended inverted 'U' in sigmoid, coffee bean sign, opposed wall sign, direction of apex of sigmoid loop, liver overlap sign, northern exposure sign and proximal colonic dilatation and CT features including whirl sign, 'X' marks the spot sign, split wall sign and number of transition points were reported for each case. The clinical management and outcomes including morbidity, mortality, endoscopic decompression and need for surgery were also evaluated. The subtype of volvulus was correlated with the above X-ray signs, CT features and clinical management and outcomes. Statistical analysis was conducted using Stata/MP, version 15 (StataCorp LP, College Station, TX, USA). RESULTS: A total of 38 scans were reviewed. There were 19 patients identified. Of these, six (32%) were reported as mesentero-axial and 13 (68%) as organo-axial volvulus. No X-ray signs were able to distinguish the two types of volvulus. The number of transition points on CT was predictive of volvulus subtype (OR 25, 95% CI: 1.30-1295.30, P = 0.01). Within the limitations of a small cohort, there was no statistically significant difference in unsuccessful endoscopic decompression, need for colectomy, repeated admissions or mortality between the groups. CONCLUSION: This study has demonstrated that organo-axial sigmoid volvulus may be as common as mesentero-axial volvulus. Distinguishing organo-axial from mesentero-axial volvulus can be achieved on CT, but not on abdominal X-ray. The number of transition points (two for mesentero-axial and one for organo-axial) may be used as a diagnostic feature for differentiating the two forms of volvulus.

Survival outcomes associated with Lynch syndrome colorectal cancer and metachronous rate after subtotal/total versus segmental colectomy: Meta-analysis.

BACKGROUND: Lynch syndrome is associated with the most common form of heritable bowel cancer. There remains limited level 1 evidence on survival outcomes and rate of metachronous tumor associated with Lynch syndrome colorectal cancer. METHODS: A systematic literature search of original studies was performed on Ovid searching MEDLINE, Embase, Cochrane Database of Systematic Reviews, American College of Physicians ACP Journal Club, Database of Abstracts of Reviews of Effects DARE, and Clinical Trials databases from inception of database to February 2021. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses reporting guideline was followed. The data were pooled using a random-effects model. All of the P values were 2-tailed, and statistical analysis was performed using RevMan v. 5.3 Cochrane Collaboration. RESULTS: From 1,942 studies, 15 studies met the inclusion criteria and were included for qualitative and quantitative synthesis. The five-year overall survival was 89.5% (82.0-94.1%), P < .01; I2 = 89%. The ten-year overall survival was 80.5% (68.7-88.6%), P < .01; I2 = 81%. The fifteen-year overall survival was 70% (33.7%-91.5%), P < .01; I2 = 93%. Univariate meta-regression analysis showed no statistically significant difference in 5-year overall survival by sex, age, MLH1, MSH2, MSH6, nor tumor location (right versus left colon). The metachronous tumor rate was 12% to 33% with a follow-up period of up to 15 years, significantly lower in patients who underwent subtotal/total colectomy (0-6%). CONCLUSION: The overall survival of patients with colorectal cancer with Lynch syndrome was approximately 90% at 5 years, 80% at 10 years, and 70% at 15 years. The metachronous tumor rate was approximately 10% to 30% at up to 15 years, significantly improved by subtotal/total colectomy.

3D mesenteric angiogram-based assessment of Arc of Riolan crossing the inferior mesenteric vein: important considerations in high ligation during splenic flexure takedown in anterior resection.

BACKGROUND: Recent studies have described the finding of the Arc of Riolan (AoR) crossing the inferior mesenteric vein (IMV) seen during high ligation of IMV while performing minimally invasive colectomies. However, the AoR usually has a medial course, and this variant AoR anatomic course and the clinical importance of its preservation during splenic flexure takedown in anterior resection remains controversial. METHODS: After institutional approval (QA-5775), radiological identification of and mapping of the vessel horizontally crossing the IMV under the pancreas, when present, was performed at a single institution (Westmead Hospital, New South Wales, Australia). One hundred consecutive computed tomographic (CT) mesenteric angiograms conducted in 2018 were reviewed retrospectively to determine the presence of a vessel horizontally crossing the IMV. 3D reconstructions were used to map out its course to understand its origin and full course. Baseline characteristics, including demographic and comorbidity data, were obtained from the medical record. RESULTS: On 3D mesenteric angiogram reconstructions, a vessel crossing anterior to the IMV was present in 11 of 98 cases (11.2%). Two cases were excluded as the presence of this vessel was indeterminate. Eight of 11 patients (72.7%) were male, and the mean age was 49.3 years (range: 21-80 years). There was no statistically significant difference in age and comorbidities between the groups. Importantly, in all 11 cases, there was an arterial vessel crossing the IMV originating from the SMA and communicating with the IMA or a branch of the IMA, proving definitively that this vessel was by definition the AoR. CONCLUSION: This 3D mesenteric angiogram mapping study has shown definitively that the vessel horizontally crossing anterior to the IMV and inferior to the pancreas is an arterial vessel from the SMA to IMA, and by definition the Arc of Riolan. When present, identification and preservation of this collateral arterial vessel during splenic flexure takedown in anterior resection may be important in reducing the risk of post-operative bowel ischaemia.

Lynch syndrome testing of colorectal cancer patients in a high-income country with universal healthcare: a retrospective study of current practice and gaps in seven australian hospitals.

BACKGROUND: To inform effective genomic medicine strategies, it is important to examine current approaches and gaps in well-established applications. Lynch syndrome (LS) causes 3-5% of colorectal cancers (CRCs). While guidelines commonly recommend LS tumour testing of all CRC patients, implementation in health systems is known to be highly variable. To provide insights on the heterogeneity in practice and current bottlenecks in a high-income country with universal healthcare, we characterise the approaches and gaps in LS testing and referral in seven Australian hospitals across three states. METHODS: We obtained surgery, pathology, and genetics services data for 1,624 patients who underwent CRC resections from 01/01/2017 to 31/12/2018 in the included hospitals. RESULTS: Tumour testing approaches differed between hospitals, with 0-19% of patients missing mismatch repair deficiency test results (total 211/1,624 patients). Tumour tests to exclude somatic MLH1 loss were incomplete at five hospitals (42/187 patients). Of 74 patients with tumour tests completed appropriately and indicating high risk of LS, 36 (49%) were missing a record of referral to genetics services for diagnostic testing, with higher missingness for older patients (0% of patients aged ≤ 40 years, 76% of patients aged > 70 years). Of 38 patients with high-risk tumour test results and genetics services referral, diagnostic testing was carried out for 25 (89%) and identified a LS pathogenic/likely pathogenic variant for 11 patients (44% of 25; 0.7% of 1,624 patients). CONCLUSIONS: Given the LS testing and referral gaps, further work is needed to identify strategies for successful integration of LS testing into clinical care, and provide a model for hereditary cancers and broader genomic medicine. Standardised reporting may help clinicians interpret tumour test results and initiate further actions.

Attitudes towards Enhanced Recovery after Surgery (ERAS) interventions in colorectal surgery: nationwide survey of Australia and New Zealand colorectal surgeons.

BACKGROUND: Whilst Enhanced Recovery after Surgery (ERAS) has been widely accepted in the international colorectal surgery community, there remains significant variations in ERAS programme implementations, compliance rates and best practice recommendations in international guidelines. METHODS: A questionnaire was distributed to colorectal surgeons from Australia and New Zealand after ethics approval. It evaluated specialist attitudes towards the effectiveness of specific ERAS interventions in improving short term outcomes after colorectal surgery. The data were analysed using a rating scale and graded response model in item response theory (IRT) on Stata MP, version 15 (StataCorp LP, College Station, TX). RESULTS: Of 300 colorectal surgeons, 95 (31.7%) participated in the survey. Of eighteen ERAS interventions, this study identified eight strategies as most effective in improving ERAS programmes alongside early oral feeding and mobilisation. These included pre-operative iron infusion for anaemic patients (IRT score = 7.82 [95% CI: 6.01-9.16]), minimally invasive surgery (IRT score = 7.77 [95% CI: 5.96-9.07]), early in-dwelling catheter removal (IRT score = 7.69 [95% CI: 5.83-9.01]), pre-operative smoking cessation (IRT score = 7.68 [95% CI: 5.49-9.18]), pre-operative counselling (IRT score = 7.44 [95% CI: 5.58-8.88]), avoiding drains in colon surgery (IRT score = 7.37 [95% CI: 5.17-8.95]), avoiding nasogastric tubes (IRT score = 7.29 [95% CI: 5.32-8.8]) and early drain removal in rectal surgery (IRT score = 5.64 [95% CI: 3.49-7.66]). CONCLUSIONS: This survey has demonstrated the current attitudes of colorectal surgeons from Australia and New Zealand regarding ERAS interventions. Eight of the interventions assessed in this study including pre-operative iron infusion for anaemic patients, minimally invasive surgery, early in-dwelling catheter removal, pre-operative smoking cessation, pre-operative counselling, avoidance of drains in colon surgery, avoiding nasogastric tubes and early drain removal in rectal surgery should be considered an important part of colorectal ERAS programmes.

Current Perspectives on the Importance of Pathological Features in Prognostication and Guidance of Adjuvant Chemotherapy in Colon Cancer.

There is not a clear consensus on which pathological features and biomarkers are important in guiding prognosis and adjuvant therapy in colon cancer. The Pathology in Colon Cancer, Prognosis and Uptake of Adjuvant Therapy (PiCC UP) Australia and New Zealand questionnaire was distributed to colorectal surgeons, medical oncologists and pathologists after institutional board approval. The aim of this study was to understand current specialist attitudes towards pathological features in the prognostication of colon cancer and adjuvant therapy in stage II disease. A 5-scale Likert score was used to assess attitudes towards 23 pathological features for prognosis and 18 features for adjuvant therapy. Data were analysed using a rating scale and graded response model in item response theory (IRT) on STATA (Stata MP, version 15; StataCorp LP). One hundred and sixty-four specialists (45 oncologists, 86 surgeons and 33 pathologists) participated. Based on IRT modelling, the most important pathological features for prognosis in colon cancer were distant metastases, lymph node metastases and liver metastases. Other features seen as important were tumour rupture, involved margin, radial margin, CRM, lymphovascular invasion and grade of differentiation. Size of tumour, location, lymph node ratio and EGFR status were considered less important. The most important features in decision making for adjuvant therapy in stage II colon cancer were tumour rupture, lymphovascular invasion and microsatellite instability. BRAF status, size of tumour, location, tumour budding and tumour infiltrating lymphocytes were factored as lesser importance. Biomarkers such as CDX2, EGFR, KRAS and BRAF status present areas for further research to improve precision oncology. This study provides the most current status on the importance of pathological features in prognostication and recommendations for adjuvant therapy in Australia and New Zealand. Results of this nationwide study may be useful to help in guiding prognosis and adjuvant treatment in colon cancer.

The impact of variations in care and complications within a colorectal Enhanced Recovery After Surgery program on length of stay.

PURPOSE: Enhanced Recovery After Surgery (ERAS) has become standard of care in colorectal surgery. However, there is not a universally accepted colorectal ERAS protocol and significant variations in care exist between institutions. The aim of this study was to examine the impact of variations in ERAS interventions and complications on length of stay (LOS). METHODS: This study was a single-center review of the first 200 consecutive patients recruited into our prospectively collected ERAS database. The primary outcome of this study was to examine the rate of compliance to ERAS interventions and the impact of these interventions on LOS. The secondary outcome was to assess the impact of complications (anastomotic leak, ileus, and surgical site infections) on LOS. ERAS interventions, rate of adherence, LOS, readmissions, morbidity, and mortality were recorded, and statistical analysis was performed. RESULTS: ERAS variations and complications significantly influenced patient LOS on both univariate and multivariate analysis. ERAS interventions identified as the most important strategies in reducing LOS included laparoscopic surgery, mobilization twice daily postoperative day (POD) 0 to 1, discontinuation of intravenous fluids on POD 0 to 1, upgrading to solid diet by POD 0 to 2, removal of indwelling catheter by POD 0 to 2, avoiding nasogastric tube reinsertion and removing drains early. Both major and minor complications increased LOS. Anastomotic leak and ileus were associated with the greatest increase in LOS. CONCLUSION: Seven high-yield ERAS interventions reduced LOS. Major and minor complications increased LOS. Reducing variations in care and complications can improve outcomes following colorectal surgery.

Pathological Features and Prognostication in Colorectal Cancer.

The prognostication of colorectal cancer (CRC) has traditionally relied on staging as defined by the Union for International Cancer Control (UICC) and American Joint Committee on Cancer (AJCC) TNM staging classifications. However, clinically, there appears to be differences in survival patterns independent of stage, suggesting a complex interaction of stage, pathological features, and biomarkers playing a role in guiding prognosis, risk stratification, and guiding neoadjuvant and adjuvant therapies. Histological features such as tumour budding, perineural invasion, apical lymph node involvement, lymph node yield, lymph node ratio, and molecular features such as MSI, KRAS, BRAF, and CDX2 may assist in prognostication and optimising adjuvant treatment. This study provides a comprehensive review of the pathological features and biomarkers that are important in the prognostication and treatment of CRC. We review the importance of pathological features and biomarkers that may be important in colorectal cancer based on the current evidence in the literature.

A Simple, Accurate and Cost-Effective Capillary Electrophoresis Test with Computational Methods to Aid in Universal Microsatellite Instability Testing.

BACKGROUND: Microsatellite instability (MSI) testing is important for the classification of Lynch syndrome, as a prognostic marker and as a guide for adjuvant chemotherapy in colorectal cancer (CRC). The gold standard for determining MSI status has traditionally been fluorescent multiplex polymerase chain reaction (PCR) and capillary gel electrophoresis (CGE). However, its use in the clinical setting has diminished and has been replaced by immunohistochemical (IHC) detection of loss of mismatch repair protein expression due to practicability and cost. The aim of this study was to develop a simple, cost-effective and accurate MSI assay based on CGE. METHOD: After amplification of microsatellites by polymerase chain reaction (PCR) using the National Cancer Institute (NCI) panel (BAT 25, BAT26, D5S346, D2S123, D17S250) of MSI markers, parallel CGE was utilized to classify colorectal cancers as MSI-H, MSI-L and MSS using the 5200 Fragment Analyzer System. Cell lines and patient cancer specimens were tested. DNA from 56 formalin-fixed paraffin-embedded cancer specimens and matched normal tissue were extracted and CGE was performed. An automated computational algorithm for MSI status determination was also developed. RESULTS: Using the fragment analyser, MSI status was found to be 100% concordant with the known MSI status of cell lines and was 86% and 87% concordant with immunohistochemistry (IHC) from patient cancer specimens using traditional assessment and our MSI scoring system, respectively, for MSI determination. The misclassification rate was mainly attributed to IHC, with only one (1.8%) sampling error attributed to CGE testing. CGE was also able to distinguish MSI-L from MSI-H and MSS, which is not possible with IHC. An MSI score based on total allelic variability that can accurately determine MSI status was also successfully developed. A significant reduction in cost compared with traditional fluorescent multiplex PCR and CGE was achieved with this technique. CONCLUSIONS: A simple, cost-effective and reliable method of determining MSI status and an MSI scoring system based on an automatic computational algorithm to determine MSI status, as well as degree of allelic instability in colorectal cancer, has been developed using the 5200 Fragment Analyzer System.

Cytotoxic CD8+ T cells and tissue resident memory cells in colorectal cancer based on microsatellite instability and BRAF status.

BACKGROUND: Recent studies in non-colorectal malignancy have associated T resident memory (TRM) cells with improved patient survival. It is unknown if TRM plays a role in colorectal cancer (CRC). AIM: To examine the potential role of TRM cells in providing immunogenicity in CRC stratified by microsatellite instability (MSI) and BRAF status. METHODS: Patients with known MSI and BRAF mutation status were eligible for inclusion in this study. CRC tumour sections stained with haematoxylin and eosin were microscopically reviewed and the images scanned prior to assessment for location of invading edge and core of tumour. Sequential sections were prepared for quantitative multiplex immunohistochemistry (IHC) staining. Opal Multiplex IHC staining was performed with appropriate positive and negative controls and imaged using a standard fluorescent microscope fitted with a spectral scanning camera (Mantra) in conjunction with Mantra snap software. Images were unmixed and annotated in inForm 2.2.0. Statistical analysis was performed using Graphpad Prism Version 7 and Stata Version 15. RESULTS: Seventy-two patients with known MSI and BRAF status were included in the study. All patients were assessed for MSI by IHC and high resolution capillary electrophoresis testing and 44 of these patients successfully underwent quantitative multiplex IHC staining. Overall, there was a statistically significant increase in CD8+ TRM cells in the MSI (BRAF mutant and wild type) group over the microsatellite stable (MSS) group. There was a statistically significant difference in CD8+ TRM between high level MSI (MSI-H):BRAF mutant [22.57, 95% confidence interval (CI): 14.31-30.84] vs MSS [8.031 (95%CI: 4.698-11.36)], P = 0.0076 andMSI-H:BRAF wild type [16.18 (95%CI: 10.44-21.93)] vs MSS [8.031 (95%CI: 4.698-11.36)], P = 0.0279. There was no statistically significant difference in CD8 T cells (both CD8+CD103- and CD8+CD103+TRM) between MSI-H: BRAF mutant and wild type CRC. CONCLUSION: This study has shown that CD8+ TRM are found in greater abundance in MSI-H CRC, both BRAF mutant and MSI-H:BRAF wild type, when compared with their MSS counterpart. CD8+ TRM may play a role in the immunogenicity in MSI-H CRC (BRAF mutant and BRAF wild type). Further studies should focus on the potential immunogenic qualities of TRM cells and investigate potential immunotherapeutic approaches to improve treatment and survival associated with CRC.

Relationship between diversional stoma and mortality rate in Fournier's gangrene: a systematic review and meta-analysis.

PURPOSE: Fournier's gangrene (FG) is a rare potentially lethal necrotising infection of the perineum. While the gold standard management is early and aggressive surgical debridement, the evidence in the literature is unclear as to the role and outcomes of diversional stoma. METHODS: A systematic review was conducted to identify studies investigating the relationship between stoma formation and FG. Meta-analyses were performed using a random-effects model. RESULTS: Twenty-seven studies (n=1482) were included. There was no significant difference in disease severity scores between the stoma and no stoma groups. Mortality rate was significantly higher in patients who required diversional stoma (OR 1.71, 95% CI 1.13-2.59, p=0.01). Significantly more surgical procedures were performed on patients who underwent stoma formation, and the total hospital cost was also higher in this group. This study may have been limited by bias in patients with more fulminant course or sphincter damage requiring stoma as a medical necessity. CONCLUSION: These findings suggest that the use of diversional stoma in FG is a predictor of poor outcomes. This study demonstrated that mortality rate remained high and a diversional stoma did not reduce risk of mortality as suggested by smaller case series. Its use should therefore be individualised based on disease severity and sphincter damage.

Bowel Preparation and Oral Antibiotic Agents for Selective Decontamination in Colorectal Surgery: Current Practice, Perspectives, and Trends in Australia and New Zealand, 2019-2020.

Background: There has been much debate as to the importance of mechanical bowel preparation (MBP) and oral antibiotic agents (OAB) prior to elective colorectal surgery over the past two decades. There is no consensus between international guidelines. Methods: The Australia and New Zealand Mechanical Bowel Preparation and Oral Antibiotics (ANZ-MBP-OAB) questionnaire was distributed to colorectal surgeons after institutional board approval assessing specialist attitudes toward 18 enhanced recovery after surgery (ERAS) interventions. Data were analyzed using a rating scale and graded response model in item response theory (IRT) on Stata MP, version 15 (StataCorp LP, College Station, TX). Specialist attitudes toward the effectiveness of MBP and OAB strategies in providing better short-term outcomes was ranked alongside other ERAS interventions. This was followed by specific questions examining current practice, perspectives, and trends. Results: Ninety-five of 300 (31.7%) colorectal surgeons in Australia and New Zealand participated in the survey. Statistical modeling was achieved in 13 ERAS interventions. Compared with other ERAS interventions, the use of MBP with OAB and MBP alone ranked nine of 13 and 10 of 13, respectively, in order of effectiveness in providing better short-term outcomes after colorectal surgery. Oral antibiotic agents alone was not considered effective. Mechanical bowel preparation with OAB was considered to be the best strategy in both colon (37%) and rectal surgery (48%) but current practice varied substantially from perspective. Mechanical bowel preparation alone was strongly favored in rectal surgery (81%) with only 14% using MBP with OAB. In colon surgery, only 10% used MBP with OAB, with MBP alone (45%) and no preparation (45%) being equally the most commonly used strategies. Conclusions: Among Australian and New Zealand colorectal surgeons, MBP with OAB was considered the best bowel preparation strategy. However, despite an awareness of its benefits, MBP with OAB has yet to be widely adopted into clinical practice or guidelines in Australia and New Zealand.