Simultaneous laparoscopic colectomy and liver metastasectomy with natural orifice specimen extraction: A proof-of-concept study.

Background, Natural orifice specimen extraction (NOSE) via the anus or vagina is an alternative to conventional transabdominal specimen extraction in laparoscopic colorectal cancer surgery. NOSE has been shown to be safe and effective, resulting in decreased postoperative pain, analgesia use, and improved recovery, without oncological compromise. We aimed to demonstrate the feasibility of NOSE for combined colectomy with liver metastasectomy. Methods, From July 2022 to April 2024, all cases of laparoscopic colorectal cancer resection and synchronous liver metastasectomy with NOSE were included in the study. Selection criteria included a maximum specimen diameter of less than 5 cm and patient body mass index of less than 35 kg/m2. Results, Over the 22-month duration, four consecutive patients (two males, two females) underwent combined resection with NOSE. Mean age and BMI were 74.8 (range 63-81) years and 20.9 (range 19.5-22.3) kg/m2 respectively. Patient A and D underwent anterior resection for sigmoid cancer, Patient B underwent D3 right hemicolectomy for cecal cancer, and Patient C underwent subtotal colectomy for synchronous cecal and descending colon cancer. All patients underwent liver metastasectomy at the same sitting. Patient A and D had transanal NOSE while Patients B and C underwent transvaginal NOSE. Mean operative time and blood loss was 416 (range 330-535) minutes and 338 (range 50-500) ml respectively. All patients recovered gastrointestinal function within the first two postoperative days. Infected seroma of the liver bed occurred in one patient requiring percutaneous drainage. The average maximum colon tumor diameter was 2.9 (range 1.3-4.0) cm. All resection margins were clear. Mean duration of follow-up was 7.5 (range 2-12) months. Conclusions, Simultaneous colectomy and liver metastasectomy with NOSE for colorectal cancer is feasible and safe in highly selected patients, resulting in good postoperative outcomes. This proof-of-concept analysis paves the way for larger studies to draw definitive conclusions.

Transvaginal versus transabdominal specimen extraction in minimally invasive surgery: a systematic review and meta-analysis.

AIM: Natural orifice specimen extraction (NOSE) is an alternative to conventional transabdominal retrieval. We aimed to compare outcomes following transvaginal specimen extraction (TVSE) and transabdominal specimen extraction (TASE) in minimally invasive abdominal surgery. METHODS: An electronic database search of PubMed, Embase and CENTRAL was performed from inception until March 2023. Comparative studies evaluating TVSE versus TASE in adult female patients were included. Studies involving transanal NOSE, endoluminal surgery, or TVSE with concomitant hysterectomy were excluded. Weighted mean differences (WMD) and odds ratio were estimated for continuous and dichotomous outcomes respectively. Primary outcomes were postoperative day 1 (POD1) pain and length of stay (LOS). Secondary outcomes were operative time, rescue analgesia, morbidity, and cosmesis. A review of sexual, oncological, and technical outcomes was performed. RESULTS: Thirteen studies (2 randomised trials, 11 retrospective cohort studies), involving 1094 patients (TASE 583, TVSE 511), were included in the analysis. Seven studies involved colorectal disease and six assessed gynaecological conditions. TVSE resulted in significantly decreased POD1 pain (WMD 1.08, 95% CI: 0.49, 1.68) and shorter LOS (WMD 1.18 days, 95% CI: 0.14, 2.22), compared to TASE. Operative time was similar between both groups, with fewer patients requiring postoperative rescue analgesia with TVSE. Overall morbidity rates, as well as both wound-related and non-wound related complication rates were better with TVSE, while anastomotic morbidity rates were comparable. Cosmetic scores were higher with TVSE. TVSE did not result in worse sexual or oncological outcomes. CONCLUSION: TVSE may be feasible and beneficial compared to TASE when performed by proficient laparoscopic operators, using appropriate selection criteria. Continued evaluation with prospective studies is warranted.

Venous thromboembolism among Asian populations with localized colorectal cancer undergoing curative resection: is pharmacological thromboprophylaxis required? A systematic review and meta-analysis.

PURPOSE: We compared the incidence of venous thromboembolism (VTE) among Asian populations with localized colorectal cancer undergoing curative resection with and without the use of pharmacological thromboprophylaxis (PTP). METHODS: A comprehensive literature search was undertaken to identify relevant studies published from January 1, 1980 to February 28, 2022. The inclusion criteria were patients who underwent primary tumor resection for localized nonmetastatic colorectal cancer; an Asian population or studies conducted in an Asian country; randomized controlled trials, case-control studies, or cohort studies; and the incidence of symptomatic VTE, deep vein thrombosis, and/or pulmonary embolism as the primary study outcomes. Data were pooled using a random-effects model. This study was registered in PROSPERO on October 11, 2020 (No. CRD42020206793). RESULTS: Seven studies (2 randomized controlled trials and 5 observational cohort studies) were included, encompassing 5,302 patients. The overall incidence of VTE was 1.4%. The use of PTP did not significantly reduce overall VTE incidence: 1.1% (95% confidence interval [CI], 0%-3.1%) versus 1.9% (95% CI, 0.3%-4.4%; P = 0.55). Similarly, PTP was not associated with significantly lower rates of symptomatic VTE, proximal deep vein thrombosis, or pulmonary embolism. CONCLUSION: The benefit of PTP in reducing VTE incidence among Asian patients undergoing curative resection for localized colorectal cancer has not been clearly established. The decision to administer PTP should be evaluated on a case-bycase basis and with consideration of associated bleeding risks.

Postoperative outcomes after prehabilitation for colorectal cancer patients undergoing surgery: a systematic review and meta-analysis of randomized and nonrandomized studies.

PURPOSE: Prehabilitation (PH) is purported to improve patients' preoperative functional status. This systematic review and meta-analysis sought to compare short-term postoperative outcomes between patients who underwent a protocolized PH program and the existing standard of care among colorectal cancer patients awaiting surgery. METHODS: A search in MEDLINE/PubMed, the Cochrane Library, Embase, Scopus, and CINAHL was conducted to identify relevant articles. Repetitive and exhaustive combinations of MeSH search terms ("prehabilitation," "colorectal cancer," "colon cancer," and "rectal cancer") were used to identify randomized and nonrandomized studies comparing PH versus standard of care for colorectal cancer patients awaiting surgery. The primary outcomes included postoperative morbidity, length of hospital stay, and readmission rates. RESULTS: Seven studies including 1,042 colorectal cancer patients (PH, 382) were included. No significant differences were found in intraoperative outcomes. The postoperative complication rates were comparable between groups (Clavien-Dindo grades I and II: risk ratio, 0.82; 95% confidence interval, 0.62-1.07; P=0.15; Clavien-Dindo grades ≥III: risk ratio, 1.02; 95% confidence interval, 0.72-1.44; P=0.92). There were also no significant differences in length of hospital stay (P=0.21) or the risk of 30-day readmission (P=0.68). CONCLUSION: Although PH does not appear to improve short-term postoperative outcomes following colorectal cancer surgery, the quality of evidence is impaired by the limited trials and heterogeneity. Thus, further large-scale trials are warranted to draw definitive conclusions and establish the long-term effects of PH.

Evaluating the surgical trainee ergonomic experience during minimally invasive abdominal surgery (ESTEEMA study).

Minimally invasive abdominal surgery (MAS) can exert a physical cost. Surgical trainees spend years assisting minimally-invasive surgeries, increasing the risk of workplace injury. This prospective questionnaire-based cohort study was conducted amongst general surgery residents in Singapore. Residents assisting major MAS surgery were invited to complete anonymous online survey forms after surgery. The Phase 1 survey assessed physical discomfort scores and risk factors. Intraoperative measures to improve ergonomics were administered and evaluated in Phase 2. During Phase 1 (October 2021 to April 2022), physical discomfort was reported in at least one body part in 82.6% (n = 38) of respondents. Over a third of respondents reported severe discomfort in at least one body part (n = 17, 37.0%). Extremes of height, training seniority, longer surgical duration and operative complexity were significant risk factors for greater physical discomfort. In Phase 2 (October 2022 to February 2023), the overall rate of physical symptoms and severe discomfort improved to 81.3% (n = 52) and 34.4% (n = 22) respectively. The ergonomic measure most found useful was having separate television monitors for the primary surgeon and assistants, followed by intraoperative feedback on television monitor angle or position. Close to 20% of survey respondents felt that surgeon education was likely to improve physical discomfort.

Using heart rate variability to develop a predictive model for post-operative cardiovascular complications following major abdominal surgery: A pilot study.

BACKGROUND: Heart Rate Variability (HRV) is a dynamic reflection of heart rhythm regulation by various physiological inputs. HRV deviations have been found to correlate with clinical outcomes in patients under physiological stresses. Perioperative cardiovascular complications occur in up to 5% of adult patients undergoing abdominal surgery and are associated with significantly increased mortality. This pilot study aimed to develop a predictive model for post-operative cardiovascular complications using HRV parameters for early risk stratification and aid post-operative clinical decision-making. METHODS: Adult patients admitted to High Dependency Units after elective major abdominal surgery were recruited. The primary composite outcome was defined as cardiovascular complications within 7 days post-operatively. ECG monitoring for HRV parameters was conducted at three time points (pre-operative, immediately post-operative, and post-operative day 1) and analyzed based on outcome group and time interactions. Candidate HRV predictors were included in a multivariable logistic regression analysis incorporating a stepwise selection algorithm. RESULTS: 89 patients were included in the analysis, with 8 experiencing cardiovascular complications. Three HRV parameters, when measured immediately post-operatively and composited with patient age, provided the basis for a predictive model with AUC of 0.980 (95% CI: 0.953, 1.00). The negative predictive value was 1.00 at a statistically optimal predicted probability cut-off point of 0.16. CONCLUSION: Our model holds potential for accelerating clinical decision-making and aiding in patient triaging post-operatively, using easily acquired HRV parameters. Risk stratification with our model may enable safe early step-down care in patients assessed to have a low risk profile of post-operative cardiovascular complications.

Stenting as bridge to surgery versus upfront emergency resection for non-metastatic left sided obstructing colorectal cancer: risk of peritoneal recurrence and long-term outcomes.

BACKGROUND: Oncological outcomes of stenting as a bridge to surgery (SBTS) remain a major concern, despite perioperative benefits it offers. This study aims to evaluate the differences in recurrence patterns and survival in patients with non-metastatic, obstructing left sided colon cancers treated by SBTS versus upfront emergency surgery (ES). METHODS: This is a retrospective, single-centre cohort study of 227 consecutive patients with non-metastatic, obstructing left sided colon cancer between 2007 and 2016. Primary outcomes were pattern of recurrence, and survival. Univariate, bivariate and multivariate logistic regression were done to determine relationships between factors and recurrence. Kaplan Meier curves and log rank tests were used to analyse survival outcomes. RESULTS: Of the 227 patients included, 62 underwent SBTS and 165 underwent upfront ES. There was a higher rate of peritoneal recurrence in SBTS group (27.4 vs 15.2% p = 0.034), with no difference observed in overall, liver or lung recurrences. No significant difference in overall survival (p = 0.11), cancer specific survival (p = 0.35), or recurrence free survival (p = 0.107) was observed. Univariate analysis showed that SBTS (OR 2.12, p = 0.036), diabetes mellitus (DM) (OR 2.58, p = 0.013), T4 (OR 2.81, p = 0.001), N + (OR 4.02, p = 0.001), lymphovascular invasion (OR 2.43, p = 0.011) contributed to a higher rate of peritoneal recurrence. Bivariate analysis showed synergistic relationship between T4 tumors and SBTS: in T4 tumors that underwent SBTS, the odds of having peritoneal recurrence was 6.8 times higher when compared to ES (p = 0.004); whilst in T2/3 tumors there was no significant difference observed (OR 1.33, p = 0.55). Multivariable analysis showed SBTS (OR 2.60, p = 0.04), DM (OR 2.88, p = 0.012), N + (OR 2.97, p = 0.026) were significant predictors for peritoneal recurrence. CONCLUSIONS: There are concerns over oncological safety of SBTS even with low rates of stent-related perforation. Higher rates of peritoneal recurrence are seen especially with T4 colon cancers treated with SBTS. SBTS, DM and nodal stage were significant predictors for peritoneal recurrence.

Intracorporeal antimesenteric ancillary trocar: an anastomotic technique facilitating natural orifice specimen extraction in left-sided colorectal surgery.

AIM: Natural orifice specimen extraction (NOSE) in left-sided colorectal surgery requires application of the circular stapler anvil to the proximal bowel without exteriorization through an additional abdominal incision. We describe an intracorporeal method to secure the stapler anvil, termed the intracorporeal antimesenteric ancillary trocar (IAAT) technique. METHOD: The ancillary trocar is attached to the stapler anvil before introduction into the abdominal cavity through the anal or vaginal orifice. The colon is incised before the trocar spike is brought out through the antimesenteric surface 3-4 cm within the cut edge. A linear stapler is used to seal the bowel end. The ancillary trocar is detached and retrieved via the NOSE conduit. Following the NOSE procedure, a side-to-end colorectal anastomosis is performed with the transanal circular stapler. RESULTS: Ten consecutive patients underwent elective left-sided colorectal resection with IAAT for NOSE (seven transanal, three transvaginal) from January to June 2023. Median age and body mass index were 66 (range 47-74) years and 24.3 (range 17.9-30.8) kg/m2 respectively. Two (20%) patients underwent sigmoid colectomy for sigmoid volvulus while eight (80%) underwent anterior resection for colorectal cancer. Median operating time, operative blood loss and postoperative length of hospital stay were 170 (range 140-240) min, 20 (range 10-40) mL and 1 (range 1-3) day respectively. There were no postoperative complications, readmissions or reoperations. Median follow-up duration was 3 (range 1-6) months. CONCLUSION: The IAAT double-stapling side-to-end anastomotic technique is safe and feasible for patients undergoing left-sided colorectal resection with NOSE, resulting in good outcomes.

Patient-reported unmet supportive care needs in long-term colorectal cancer survivors after curative treatment in an Asian population.

OBJECTIVES: Despite an increase in colorectal cancer (CRC) survival, less is known about CRC-specific long-term unmet supportive needs in Asian patients. This study aimed to examine the prevalence of long-term unmet needs and identify clinical and socio-demographic factors associated with increased unmet needs in Asian CRC survivors. DESIGN AND SETTING: We conducted a cross-sectional study that assessed unmet needs using the Cancer Survivors' Unmet Needs scale. CRC survivors of at least two years after undergoing curative surgery were recruited from an outpatient clinic of a large public hospital in Singapore. RESULTS: In total, 400 CRC survivors with a mean age of 64 and a median survival time post-surgery of 78 months participated in the study. Approximately half of patients (52%) reported at least one unmet need. Male gender (RR 1.19, p = 0.01), age greater than 65 years (RR 0.63, p < 0.0001), longer follow up of more than 5 years (RR 0.80, p = 0.009), presence of a permanent stoma (RR 1.78, p < 0.0001), prior radiotherapy in treatment course (RR 1.99, p < 0.0001), higher educational status (RR 1.30, p = 0.0002), currently employed (RR 0.84, p = 0.014), currently married (RR 0.84, p = 0.01) were significant predictors for increased unmet needs. CONCLUSION: There is a high prevalence of unmet needs in long-term Asian CRC survivors, which underscores the importance of screening patients to allow for early detection of unmet needs. Our findings on sociodemographic and clinical predictors can inform the development of targeted interventions tailored to the need domains and improvement of survivorship programmes.

Transvaginal Natural Orifice Specimen Extraction (NOSE) in Laparoscopic Colorectal Cancer Surgery With New Insights on Technique and Patient Selection.

BACKGROUND: Following laparoscopic colorectal surgery, transabdominal specimen extraction requires a mini-laparotomy or Pfannenstiel incision, associated with increased postoperative pain and wound complications. The vagina has several unique properties that make natural orifice specimen extraction (NOSE) ideal. We report our experience with transvaginal NOSE for colorectal cancer surgery. MATERIALS AND METHODS: A transvaginal sizer allows the posterior vagina to be incised under tension. A transverse or cruciate incision is made, followed by the insertion of a double-ring wound protector. The external ring is opened against the perineum to shorten the length of the conduit for specimen delivery. Vaginotomy closure is performed via laparoscopy using a barbed suture. RESULTS: Seventeen consecutive female patients underwent elective colorectal cancer surgery with attempted transvaginal NOSE. Median age and body mass index was 67 (range: 50 to 82) years and 26.5 (range: 19.7 to 35.8) kg/m 2 , respectively. Fourteen patients (82%) underwent left-sided resections and 3 (18%) underwent right-sided resections. Median operating time, blood loss, and length of hospital stay was 245 (range: 155 to 360) minutes, 30 (range: 10 to 500) mL, and 3 (range: 2 to 9) days, respectively. Transvaginal extraction was unsuccessful in 1 (6%) patient. Two (12%) patients experienced early postoperative morbidity, neither attributable to the extraction procedure. Median tumor circumferential diameter was 3.3 (range: 2.2 to 7.0) cm. Median follow-up duration was 17 (range: 8 to 27) months. There was no instance of sexual dysfunction. CONCLUSIONS: Transvaginal NOSE for colorectal cancer surgery is feasible and safe in selected patients. Overall specimen diameter, inclusive of tumor and mesentery, relative to pelvic outlet and conduit diameter is the most important consideration for transvaginal NOSE.

Incidence of incisional hernia after major colorectal cancer surgery & analysis of associated risk factors in Asian population: Is laparoscopy any better?

BACKGROUND: Incisional hernia is one of the common morbidities after major colorectal cancer surgery. We aim to compare the incidence of incisional hernias between laparoscopic and open surgery. We also aim to identify associated risk factors of incisional hernia among Asian population who has undergone major resection for colorectal cancer. METHODS: Data of patients who had undergone major colorectal cancer surgery in year 2015 from a single institution was collected. Data were extracted from electronic clinical records from our institution's database. Incisional hernias were identified by clinical examination and computed tomography (CT) scan performed during post-operative follow up as part of colorectal cancer surveillance. Follow up data of up to 3 years were extracted. Univariate and multivariable logistic regression analysis were performed to identify associated risk factors for development of incisional hernia. Propensity score matching analysis was performed for laparoscopic and open resection. RESULTS: 502 patients were included in the study. With a minimum follow up of 3 years, overall incisional hernia incidence rate of 13% was identified. Incisional hernias after laparoscopic and open surgery were 12.3% and 13.8% (p = 0.688) respectively. Univariate logistic regression analysis showed that body mass index (BMI) of >23kg/m2, ASA of III/IV and post-operative anastomotic leak were associated with development of incisional hernias. On multivariable analysis, female gender (OR 2.102, 95%CI: 1.155, 3.826), BMI of ≥23 kg/m2 (OR 2.862 95%CI: 1.582, 5.181), ASA III/IV (OR 2.052, 95%CI: 1.169, 3.602), were significantly associated with development of incisional hernia. Propensity scores matched analysis showed laparoscopic surgery did not significantly reduce the incidence of incisional hernia. CONCLUSION: The overall incidence of incisional hernia seems lower in Asian population. Our study demonstrated no significant difference in incisional hernia rates between patients undergoing laparoscopic versus open colorectal cancer surgery. Female gender, higher BMI, and higher ASA are associated with increased risk of developing incisional hernia after major colorectal cancer resection.

Efficacy of biofeedback therapy for faecal incontinence in an Asian population.

BACKGROUND: Faecal incontinence (FI) is a debilitating condition which reduces quality of life (QOL). Conservative management with education, pelvic floor exercise and pharmacological agents are first-line treatment. Following which, biofeedback therapy (BFT) is recommended. Although well described in the West, existing literature on its efficacy in Asian populations remains sparse. The primary aim of our study is to evaluate the efficacy of BFT in improvement of symptoms, QOL and overall satisfaction in our Asian population. METHODS: Patients with moderate FI in Singapore General Hospital between 2012 and 2016 were enrolled. Rockwood FI quality of life scale (FIQL) and Wexner scale were used to evaluate QOL across four domains, and symptom severity respectively. They were scored at baseline and again after four sessions of BFT, with an additional overall satisfaction score (OSS). RESULTS: A total of 137 patients were included. Mean age was 62 years and 72.3% were female. Majority demonstrated improvement in Wexner score (68.6%) and FIQL (65%). Sixty-five patients (47.4%) reported improvement in both. Positive correlation was found between Wexner score and OSS (r = 0.206), and Wexner score and FIQL across all four domains. Only one FIQL domain-coping/behaviour, showed statistically significant correlation with OSS (r = 0.263). CONCLUSION: BFT is effective in our Asian population in both symptom reduction and improving QOL. Wexner score demonstrated low correlation with FIQL and OSS-suggesting that FI requires a multi-dimensional approach beyond symptom treatment, of which ability to cope appears crucial. BFT, consistent with the biopsychosocial model, shows benefit in this regard.

Cost-effectiveness comparison of delayed versus immediate coloanal anastomosis following ultralow anterior resection for rectal cancer.

BACKGROUND: Following ultralow anterior resection for distal rectal cancers, a coloanal anastomosis is usually created along with a defunctioning ileostomy (DI). Recent evidence suggests that abdominoperineal pull-through with delayed coloanal anastomosis (DCAA) is a viable alternative to immediate coloanal anastomosis (ICAA), minimizing the risk of anastomotic leakage and avoiding the need for stoma creation with the risk of stoma-associated morbidity. However, DCAA requires a longer initial hospitalization. We aimed to perform a cost-effectiveness analysis to compare DCAA versus ICAA for elective rectal cancer surgery. METHODS: A decision tree model was used to compare the cost-effectiveness of the two strategies. Cost data were obtained from the 2019 to 2020 United Kingdom National Health Service reference costs. Model probabilities were derived from published studies. Univariate and probabilistic sensitivity analyses were used to evaluate the robustness of the results. RESULTS: DCAA was the overall cheaper strategy at £13 541 compared with £14 856 for ICAA in the base case analysis. This was explained by the decreased overall costs of hospitalization/surgery, reduction in costs associated with anastomotic or stoma-related complications, specifically dehydration-induced hospital readmissions and avoidance of stoma maintenance costs. Sensitivity analysis demonstrated that DCAA remained consistently more inexpensive except when the duration of total parenteral nutrition exceeded 14 days. CONCLUSION: Despite a longer index hospitalization with higher initial costs, this economic analysis demonstrates that DCAA without stoma is overall more cost-effective compared with ICAA with DI following ultralow anterior resection. Cost savings should be considered an additional benefit when selecting the DCAA approach for rectal cancer surgery.

Survival outcomes of salvage surgery in the watch-and-wait approach for rectal cancer with clinical complete response after neoadjuvant chemoradiotherapy: a systematic review and meta-analysis.

PURPOSE: This systematic review and meta-analysis compared the outcomes of the watch-and-wait (WW) approach versus radical surgery (RS) in rectal cancers with clinical complete response (cCR) after neoadjuvant chemoradiotherapy. METHODS: This study followed the PRISMA guidelines. Major databases were searched to identify relevant articles. WW and RS were compared through meta-analyses of pooled proportions. Primary outcomes included overall survival (OS), disease-free survival (DFS), local recurrence, and distant metastasis rates. Pooled salvage surgery rates and outcomes were also collected. The Newcastle-Ottawa scale was employed to assess the risk of bias. RESULTS: Eleven studies including 1,112 rectal cancer patients showing cCR after neoadjuvant chemoradiation were included. Of these patients, 378 were treated nonoperatively with WW, 663 underwent RS, and 71 underwent local excision. The 2-year OS (risk ratio [RR], 0.95; P = 0.94), 5-year OS (RR, 2.59; P = 0.25), and distant metastasis rates (RR, 1.05; P = 0.80) showed no significant differences between WW and RS. Local recurrence was more frequent in the WW group (RR, 6.93; P < 0.001), and 78.4% of patients later underwent salvage surgery (R0 resection rate, 97.5%). The 2-year DFS (RR, 1.58; P = 0.05) and 5-year DFS (RR, 2.07; P = 0.02) were higher among RS cases. However, after adjustment for R0 salvage surgery, DFS showed no significant between-group difference (RR, 0.82; P = 0.41). CONCLUSION: Local recurrence rates are higher for WW than RS, but complete salvage surgery is often possible with similar long-term outcomes. WW is a viable strategy for rectal cancer with cCR after neoadjuvant chemoradiation, but further research is required to improve patient selection.

The distinct clinical trajectory, metastatic sites, and immunobiology of microsatellite-instability-high cancers.

Microsatellite-instability-high (MSI-H) cancers form a spectrum of solid organ tumors collectively known as Lynch Syndrome cancers, occurring not only in a subset of colorectal, endometrial, small bowel, gastric, pancreatic, and biliary tract cancers but also in prostate, breast, bladder, and thyroid cancers. Patients with Lynch Syndrome harbor germline mutations in mismatch repair genes, with a high degree of genomic instability, leading to somatic hypermutations and, therefore, oncogenesis and cancer progression. MSI-H cancers have unique clinicopathological characteristics compared to their microsatellite-stable (MSS) counterparts, marked by a higher neoantigen load, immune cell infiltration, and a marked clinical response to immune checkpoint blockade. Patients with known Lynch Syndrome may be detected early through surveillance, but some patients present with disseminated metastatic disease. The treatment landscape of MSI-H cancers, especially colorectal cancers, has undergone a paradigm shift and remains to be defined, with immune checkpoint blockade coming to the forefront of treatment strategies in the stage IV setting. We summarize in this review the clinical features of MSI-H cancers with a specific interest in the pattern of spread or recurrence, disease trajectory, and treatment strategies. We also summarize the tumor-immune landscape and genomic profile of MSI-H cancers and potential novel therapeutic strategies.

Outcomes after natural orifice extraction vs conventional specimen extraction surgery for colorectal cancer: A propensity score-matched analysis.

BACKGROUND: Natural orifice specimen extraction (NOSE) via the anus or vagina replaces conventional transabdominal specimen retrieval via the transabdominal route through a limited mid-line laparotomy or Pfannenstiel incision. Reducing the number of laparoscopic ports further decreases operative abdominal wall trauma. These techniques reduce the surgical wound size as well as the risk of incision-related morbidity. AIM: To compare short-term outcomes following 3-port NOSE surgery with a matched cohort of conventional non-NOSE colorectal cancer surgery. METHODS: Patients who underwent elective 3-port laparoscopic colorectal NOSE surgery between February to October 2021 were identified. Selection criteria for NOSE surgery was adapted from the 2019 International Consensus on Natural Orifice Specimen Extraction Surgery for colorectal cancer. Patients with clinical T4 or N2 tumors on staging computed tomography were also excluded. The propensity score-matched cohort was identified amongst patients who underwent conventional laparoscopic colorectal surgery from January 2019 to December 2020. Matching was performed in the ratio of 1:4 based on age, gender, type of resection, and p - tumor node metastasis staging. RESULTS: Over the eight-month study duration, 14 consecutive cases (nine female, five male) of elective 3-port laparoscopic surgery with NOSE were performed for colorectal cancer. Median age and body mass index were 70 (range 43-82) years and 24.1 (range 20.0-31.7) kg/m2 respectively. Six patients underwent transanal NOSE and eight had transvaginal NOSE. Median operative time, intraoperative blood loss and postoperative length of stay were 208 (range 165-365) min, 30 (range 10-150) mL and 3 (range 2-6) d respectively. Two (14%) suffered minor postoperative compilations not attributable to the NOSE procedure. Median follow-up duration was 12 (range 8-15) mo. No instances of mortality, local or distant disease recurrence were recorded in this cohort. Compared to the conventional surgery cohort of 56 patients, the 3-port NOSE cohort had significantly quicker mean return of bowel function (2.6 vs 1.2 d, P < 0.001), reduced postoperative pain and patient-controlled analgesia use, and decreased length of hospital stay (6.4 vs 3.4 d, P < 0.001). There were no statistical differences in surgical duration and perioperative complication rates between the NOSE and non-NOSE cohorts. CONCLUSION: 3-port laparoscopic colorectal surgery with NOSE is a feasible technique, augmenting the minimally invasive nature of surgery and producing good outcomes. Appropriate patient selection and expertise in conventional laparoscopy are required.