Robotic-assisted low anterior resection for rectal cancer shows similar clinical efficacy to laparoscopic surgery: A propensity score matched study

BACKGROUND Rectal cancer ranks as the second leading cause of cancer-related mortality worldwide,necessitating surgical resection as the sole treatment option.Over the years,there has been a growing adoption of minimally invasive surgical techni-ques such as robotic and laparoscopic approaches.Robotic surgery represents an innovative modality that effectively addresses the limitations associated with traditional laparoscopic techniques.While previous studies have reported favo-rable perioperative outcomes for robot-assisted radical resection in rectal cancer patients,further evidence regarding its oncological safety is still warranted.AIM To conduct a comparative analysis of perioperative and oncological outcomes between robot-assisted and laparoscopic-assisted low anterior resection(LALAR)procedures.METHODS The clinical data of 125 patients who underwent robot-assisted low anterior resection(RALAR)and 279 patients who underwent LALAR resection at Shandong Provincial Hospital Affiliated to Shandong First Medical University from December 2019 to November 2022 were retrospectively analyzed.After performing a 1:1 propensity score matching,the patients were divided into two groups:The RALAR group and the LALAR group(111 cases in each group).Subsequently,a comparison was made between the short-term outcomes within 30 d after surgery and the 3-year survival outcomes of these two groups.RESULTS Compared to the LALAR group,the RALAR group exhibited a significantly earlier time to first flatus[2(2-2)d vs 3(3-3)d,P=0.000],as well as a shorter time to first fluid diet[4(3-4)d vs 5(4-6)d,P=0.001].Additionally,the RALAR group demonstrated reduced postoperative indwelling catheter time[2(1-3)d vs 4(3-5)d,P=0.000]and decreased length of hospital stay after surgery[5(5-7)d vs 7(6-8)d,P=0.009].Moreover,there was an observed increase in total cost of hospitalization for the RALAR group compared to the LALAR group[10777(10780-11850)dollars vs 10550(8766-11715)dollars,P=0.012].No significant differences were found in terms of conversion rate to laparotomy or incidence of postoperative complications between both groups.Furthermore,no significant disparities were noted regarding the 3-year overall survival rate and 3-year disease-free survival rate between both groups.CONCLUSION Robotic surgery offers potential advantages in terms of accelerated recovery of gastrointestinal and urologic function compared to LALAR resection,while maintaining similar perioperative and 3-year oncological outcomes.

To explore the pathogenesis of anterior resection syndrome by magnetic resonance imaging rectal defecography

BACKGROUND Over 90%of rectal cancer patients develop low anterior resection syndrome(LARS)after sphincter-preserving resection.The current globally recognized evaluation method has many drawbacks and its subjectivity is too strong,which hinders the research and treatment of LARS.AIM To evaluate the anorectal function after colorectal cancer surgery by quantifying the index of magnetic resonance imaging(MRI)defecography,and pathogenesis of LARS.METHODS We evaluated 34 patients using the standard LARS score,and a new LARS evaluation index was established using the dynamic images of MRI defecography to verify the LARS score.RESULTS In the LARS score model,there were 10(29.41%)mild and 24(70.58%)severe cases of LARS.The comparison of defecation rate between the two groups was 29.36±14.17%versus 46.83±18.62%(P=0.004);and MRI-rectal compliance(MRI-RC)score was 3.63±1.96 versus 7.0±3.21(P=0.001).Severe and mild LARS had significant differences using the two evaluation methods.There was a significant negative correlation between LARS and MRI-RC score(P<0.001),and they had a negative correlation with defecation rate(P=0.028).CONCLUSION MRI defecography and standard LARS score can both be used as an evaluation index to study the pathogenesis of LARS.

Efficacy of laparoscopic low anterior resection for colorectal cancer patients with 3D-vascular reconstruction for left coronary artery preservation

BACKGROUND Laparoscopic low anterior resection(LLAR)has become a mainstream surgical method for the treatment of colorectal cancer,which has shown many advantages in the aspects of surgical trauma and postoperative rehabilitation.However,the effect of surgery on patients'left coronary artery and its vascular reconstruction have not been deeply discussed.With the development of medical imaging technology,3D vascular reconstruction has become an effective means to evaluate the curative effect of surgery.AIM To investigate the clinical value of preoperative 3D vascular reconstruction in LLAR of rectal cancer with the left colic artery(LCA)preserved.METHODS A retrospective cohort study was performed to analyze the clinical data of 146 patients who underwent LLAR for rectal cancer with LCA preservation from January to December 2023 in our hospital.All patients underwent LLAR of rectal cancer with the LCA preserved,and the intraoperative and postoperative data were complete.The patients were divided into a reconstruction group(72 patients)and a nonreconstruction group(74 patients)according to whether 3D vascular reconstruction was performed before surgery.The clinical features,operation conditions,complications,pathological results and postoperative recovery of the two groups were collected and compared.RESULTS A total of 146 patients with rectal cancer were included in the study,including 72 patients in the reconstruction group and 74 patients in the nonreconstruction group.There were 47 males and 25 females in the reconstruction group,aged(59.75±6.2)years,with a body mass index(BMI)(24.1±2.2)kg/m^(2),and 51 males and 23 females in the nonreconstruction group,aged(58.77±6.1)years,with a BMI(23.6±2.7)kg/m^(2).There was no significant difference in the baseline data between the two groups(P>0.05).In the submesenteric artery reconstruction group,35 patients were type Ⅰ,25 patients were type Ⅱ,11 patients were type Ⅲ,and 1 patient was type Ⅳ.There were 37 type Ⅰ patients,24 type Ⅱ patients,12 type Ⅲ patients,and 1 type Ⅳ patient in the nonreconstruction group.There was no significant difference in arterial typing between the two groups(P>0.05).The operation time of the reconstruction group was 162.2±10.8 min,and that of the nonreconstruction group was 197.9±19.1 min.Compared with that of the reconstruction group,the operation time of the two groups was shorter,and the difference was statistically significant(t=13.840,P<0.05).The amount of intraoperative blood loss was 30.4±20.0 mL in the reconstruction group and 61.2±26.4 mL in the nonreconstruction group.The amount of blood loss in the reconstruction group was less than that in the control group,and the difference was statistically significant(t=-7.930,P<0.05).The rates of anastomotic leakage(1.4%vs 1.4%,P=0.984),anastomotic hemorrhage(2.8%vs 4.1%,P=0.672),and postoperative hospital stay(6.8±0.7 d vs 7.0±0.7 d,P=0.141)were not significantly different between the two groups.CONCLUSION Preoperative 3D vascular reconstruction technology can shorten the operation time and reduce the amount of intraoperative blood loss.Preoperative 3D vascular reconstruction is recommended to provide an intraoperative reference for laparoscopic low anterior resection with LCA preservation.

Machine learning model for prediction of low anterior resection syndrome following laparoscopic anterior resection of rectal cancer:A multicenter study

BACKGROUND Low anterior resection syndrome(LARS)severely impairs patient postoperative quality of life,especially major LARS.However,there are few tools that can accurately predict major LARS in clinical practice.AIM To develop a machine learning model using preoperative and intraoperative factors for predicting major LARS following laparoscopic surgery of rectal cancer in Chinese populations.METHODS Clinical data and follow-up information of patients who received laparoscopic anterior resection for rectal cancer from two medical centers(one discovery cohort and one external validation cohort)were included in this retrospective study.For the discovery cohort,the machine learning prediction algorithms were developed and internally validated.In the external validation cohort,we evaluated the trained model using various performance metrics.Further,the clinical utility of the model was tested by decision curve analysis.RESULTS Overall,1651 patients were included in the present study.Anastomotic height,neoadjuvant therapy,diverting stoma,body mass index,clinical stage,specimen length,tumor size,and age were the risk factors associated with major LARS.They were used to construct the machine learning model to predict major LARS.The trained random forest(RF)model performed with an area under the curve of 0.852 and a sensitivity of 0.795(95%CI:0.681-0.877),a specificity of 0.758(95%CI:0.671-0.828),and Brier score of 0.166 in the external validation set.Compared to the previous preoperative LARS score model,the current model exhibited superior predictive performance in predicting major LARS in our cohort(accuracy of 0.772 for the RF model vs 0.355 for the preoperative LARS score model).CONCLUSION We developed and validated a robust tool for predicting major LARS.This model could potentially be used in the clinic to identify patients with a high risk of developing major LARS and then improve the quality of life.

Effect of low anterior resection syndrome on quality of life in colorectal cancer patients:A retrospective observational study

BACKGROUND Low anterior resection syndrome(LARS)is a common complication of anuspreserving surgery in patients with colorectal cancer,which significantly affects patients'quality of life.AIM To determine the relationship between the incidence of LARS and patient quality of life after colorectal cancer surgery and to establish a LARS prediction model to allow perioperative precision nursing.METHODS We reviewed the data from patients who underwent elective radical resection for colorectal cancer at our institution from April 2013 to June 2020 and completed the LARS score questionnaire and the European Organization for Research and Treatment of Cancer Core Quality of Life and Colorectal Cancer Module questionnaires.According to the LARS score results,the patients were divided into no LARS,mild LARS,and severe LARS groups.The incidence of LARS and the effects of this condition on patient quality of life were determined.Univariate and multivariate analyses were performed to identify independent risk factors for the occurrence of LARS.Based on these factors,we established a risk prediction model for LARS and evaluated its performance.RESULTS Among the 223 patients included,51 did not develop LARS and 171 had mild or severe LARS.The following quality of life indicators showed significant differences between patients without LARS and those with mild or severe LARS:Physical,role,emotional,and cognitive function,total health status,fatigue,pain,shortness of breath,insomnia,constipation,and diarrhea.Tumor size,partial/total mesorectal excision,colostomy,preoperative radiotherapy,and neoadjuvant chemotherapy were identified to be independent risk factors for LARS.A LARS prediction model was successfully established,which demonstrated an accuracy of 0.808 for predicting the occurrence of LARS.CONCLUSION The quality of life of patients with LARS after colorectal cancer surgery is significantly reduced.

Application of electroacupuncture in the prevention of low anterior resection syndrome after rectal cancer surgery

BACKGROUND Low anterior resection syndrome(LARS)is one of the common postoperative complications in patients with rectal cancer,which seriously affects their postoperative recovery and quality of life(QoL).Electroacupuncture therapy is one of the characteristic therapies of traditional Chinese medicine.There are few reports on the prevention and treatment of LARS by electroacupuncture therapy.AIM To explore the clinical effectiveness of electroacupuncture in managing rectal cancer patients with postoperative LARS.METHODS A total of 50 patients with LARS after rectal cancer surgery were retrospectively selected as the research subjects.According to the treatment methods,they were divided into an observation group(n=25)and a control group(n=25).During the four-week treatment period,the control group received standard defecation function training,while the observation group received electroacupuncture care and traditional defecation function training.The anal pressure index(which includes anal resting pressure,anal systolic pressure,and maximum tolerable volume),European Organization of Research and Treatment of Cancer(EORTC)QoL C30(QLQ-C30)score,LARS Scale(LARSS)score,Wexner anal incontinence scale score,Xu Zhongfa five-item 10-point scale score,and the occurrence of adverse reactions were compared between the two groups before and after treatment.RESULTS The experimental group showed considerably enhanced LARSS scores compared to those in the control group after four weeks of treatment.In the first week,second week,and fourth week,the LARSS score and Wexner anal incontinence scale score decreased,and the Xu Zhong method five-item 10-point scale score increased,with significant differences(P<0.05).The experimental group showed substantial improvements in anal resting pressure,anal systolic pressure,and maximum tolerance volume after undergoing 4 wk of therapy in the untreated group(P<0.05).The experimental group's QLQ-C30 score on the EORTC QoL questionnaire was higher than that of the control group during the 1st,2nd,and 4th wk(P<0.05).No significant variation between the groups in the frequency of adverse reactions(P>0.05)was observed.CONCLUSION Electroacupuncture positively impacted LARS following rectal cancer surgery,effectively improving clinical symptoms and anal pressure indicators and patients’standard of life.

Anterior resection for rectal carcinoma-risk factors for anastomotic leaks and strictures

AIM:To determine the incidence and factors responsible for anastomotic leaks and stricture following anterior resection(AR)and its subsequent management.METHODS:Retrospective analysis of data from 108 patients with rectal carcinoma who underwent AR or low anterior resection(LAR)to identify the various preoperative,operative,and post operative factors that might have influence on anastomotic leaks and strictures.RESULTS:There were 68 males and 40 females with an average of 47 years(range 21-75 years).The median distance of the tumor from the anal verge was 8 cm(range 3-15 cm).Sixty(55.6%)patients underwent handsewn anastomosis and 48(44.4%)were stapled.The median operating time was 3.5 h(range2.0-7.5 h).Sixteen(14.6%)patients had an anastomotic leak.Among these,11 patients required reexploration and five were managed expectantly.The anastomotic leak rate was similar in patients with and without diverting stoma(8/60,13.4%with stoma and 8/48;16.7%without stoma).In 15(13.9%)patients,resection margins were positive for malignancy.Ninteen(17.6%)patients developed anastomotic strictures at a median duration of 8 mo(range 3-20 mo).Among these,15 patients were successfully managed with per-anal dilatation.On multivariate analysis,advance age(>60 years)was the only risk factor for anastomotic leak(P=0.004).On the other hand,anastomotic leak(P=0.00),mucin positive tumor(P =0.021),and lower rectal growth(P=0.011)were found as risk factors for the development of an anastomotic stricture.CONCLUSION:Advance age is a risk factor for an anastomotic leak.An anastomotic leak,a mucin-secreting tumor,and lower rectal growth predispose patients to develop anastomotic strictures.

Transanal natural orifice specimen extraction for laparoscopic anterior resection in rectal cancer

AIM: To investigate whether transanal natural orifice specimen extraction (NOSE) is a better technique for rectal cancer resection.METHODS: A prospectively designed database of a consecutive series of patients undergoing laparoscopic low anterior resection for rectal cancer with various tumor-node-metastasis classi?cations from March 2011 to February 2012 at the First Affiliated Hospital of Sun Yat-Sen University was analyzed. Patient selection for transanal specimen extraction and intracorporeal anastomosis was made on the basis of tumor size and distance of rectal lesions from the anal verge. Demographic data, operative parameters, and postoperative outcomes were assessed.RESULTS: None of the patients was converted to laparotomy. Respectively, there were 16 cases in the low anastomosis and five in the ultralow anastomosis groups. Mean age of the patients was 45.4 years, and mean body mass index was 23.1 kg/m2. Mean distance of the lower edge of the lesion from the anal verge was 8.3 cm. Mean operating time was 132 min, and mean intraoperative blood loss was 84 mL. According to the principle of rectal cancer surgery, we performed D2 lymph node dissection in 13 cases and D3 in eight. Mean lymph nodes harvest was 17.8, and the number of positive lymph nodes was 3.4. Median hospital stay was 6.7 d. No serious postoperative complication occurred except for one anastomotic leakage. All patients remained disease free. Mean Wexner score was 3.7 at 11 mo after the operation.CONCLUSION: Transanal NOSE for total laparoscopic low/ultralow anterior resection is feasible, safe and oncologically sound. Further studies with long-term outcomes are needed to explore its potential advantages.

Role of protective stoma in low anterior resection for rectal cancer:A meta-analysis

AIM: To provide a comprehensive evaluation of the role of a protective stoma in low anterior resection (LAR) for rectal cancer.

Colonic J-pouch anal anastomosis after ultralow anterior resection with upper sphincter excision for low-lying rectal cancer

AIM:There is some evidence of functional superiority of colonic J-pouch over straight coloanal anastomosis (CM) in ultralow anterior resection (ULAR) or intersphincteric resection. On the assumption that colonic J-pouch anal anastomosis is superior to straight CM in ULAR with upper sphincter excision (USE: excision of the upper part of the internal sphincter) for low-lying rectal cancer, we compare functional outcome of colonic J-pouch vsthe straight CM. METHODS: Fifty patients of one hundred and thirty-three rectal cancer patients in whom lower margin of the tumors were located between 3 and 5 cm from the anal verge received ULAR including USE from September 1998 to January 2002. Patients were randomized for reconstruction using either a straight (n = 26) or a colonic J-pouch anastomosis (n = 24) with a temporary diverting-loop ileostomy. All patients were followed-up prospectively by a standardized questionnaire [Fecal Inco-ntinence Severity Index (FISI) scores and Fecal Incontinence Quality of Life (FIQL) scales]. RESULTS: We found that, compared to straight anastomosis patients, the frequency of defecation was significantly lower in J-pouch anastomosis patients for 10 mo after ileostomy takedown. The FISI scores and FIQL scales were significantly better in J-pouch patients than in straight patients at both 3 and 12 mo after ileostomy takedown. Furthermore, we found that FISI scores highly correlated with FIQL scales. CONCLUSION: This study indicates that colonic J-pouch anal anastomosis decreases the severity of fecal incontinence and improves the quality of life for 10 mo after ileostomy takedown in patients undergoing ULAR with USE for low-lying rectal cancer.

Expressions of Connexin and Par-3 in the Distal Margin of Rectal Cancer after Ultra-low Anterior Resection

This study examined the expression of connexin and protease-activated receptor 3 （par-3） in the distal resection margin of rectal cancer and the correlation of the expression of the two proteins with tumor relapse. A total of 40 patients with rectal cancer underwent ultra-low anterior resection with curved cutter stapler. The pathological specimens were divided into 3 groups in terms of sampling sites： tumor group, 2.0-cm group （in which the tissues were harvested 2.0 cm distal to the tumor tissues）, 3.0-cm group （in which the tissues were taken 3.0 cm away from the tumor tissues）. All the samples were pathologically observed and then measured for the expression of connexin and par-3 by employing immunohistochemistry and Western blotting. The operations in this series went uneventfully. No anastomotic stoma bleeding, stenosis and death occurred postoperatively. Histopathologically, in the tumor group, epithelial cells lost normal pattern of arrangement and polarity, and were loosely connected and even detached. In the 3.0-cm group, the epithelia had normal appearance, obvious cell polarity and essentially intact cell junction. Immunohistochemistry and Western blotting indicated that the 3.0-cm group had the strongest expression of connexin and par-3, and the expression in the 2.0-cm group and the tumor group was relatively weak. There existed significant difference in the expression of the two proteins among the three groups （P〈0.05 for all）. It was concluded that the down-regulated connexin and par-3 in the distal margin of rectal cancer tissues may indicate the progression of the disease and high likelihood of recurrence and metastasis. Although no tumor cells were found in the sections of the 2.0cm group, the decreased expression of connexin and par-3 may suggest the development of anaplasia and the increased odds of tumor relapse. Therefore, we are led to speculate that tumor resection only including 2.0 cm of unaffected rectum could not completely avoid the distant metastasis and local relapse.

LOW ANTERIOR RESECTION TREATMENT FOR MIDDLE AND LOWER RECTAL CANCER

Objective:To evaluate the results of low anteriorresection treatment for middle and lower rectal cancer. Methods:Clinical and follow-up data of 196 patients with middle and lower rectal cancer who received low anteriorresection treatment from June 1991 to June 2001 wereretrospectively analyzed. Results: anterior resectiontechnique including double stapling technique、pull-through and Park抯 operations could get a standard radicalresection and had no significant differences in 1, 3, 5 and 10 years survival rates comparing with the abdominoperineal resection(Miles?. Conclusion:The experience suggests that the low anterior resection technique was safe and simplehad less bleeding and fewer complications and couldincrease the life-quality of the patients with rectal cancer.

Risk factors for anastomotic leakage after low anterior resection without diversional stomas

Objective The most important complication after low anterior resection(LAR) for mid-low rectal cancer is symptomatic anastomotic leakage(AL). More than one-third of patients with rectal cancer who underwent LAR will have functional stomas during primary operation. The aim of this retrospective study was to evaluate the risk factors associated with clinical AL following LAR without diversional stomas.Methods Between 2012 and 2017, information about 578 consecutive patients with rectal tumors less than 12 cm from the anal verge who underwent LAR without diversional stomas by the same surgical team was collected retrospectively. A standardized extraperitonealized anastomosis and pelvic drainage were conducted for all patients during primary operations, and the outcome of interest was clinical AL. The associations between AL and 14 patient-related and surgical variables were examined by both univariate chi-square test and multivariate logistic regression analysis.Results The AL rate was 7.27%(42 of 578). Univariate and multivariate analyses showed that male sex(P = 0.018), mid-low rectal cancer(located 10 cm or less above the anal verge)(P = 0.041), presence of diabetes(odds ratio = 2.117), longer duration of operation(odds ratio = 1.890), and intraoperative contamination(odds ratio = 2.163) were risk factors of AL for LAR without diversional stoma and independently predictive of clinical AL. Nearly 83.3%(35 of 42) of leakage could be cured by persistent pelvic irrigation-suction-drainage without surgical intervention. Only 7 patients(16.7%) with severe complications, such as peritonitis, and fistula, required reoperation, and functional stoma was used as a salvage treatment.Conclusion From the findings of this retrospective survey, we identified that mid-low rectal cancer and male sex were independent risk factors for developing clinical AL after LAR without diversional stomas, as well as longer duration of operation, presence of diabetes, and contamination of the operative field. Moreover, we deemed that LAR without diversional stomas for mid-low rectal cancers was safe, effective, and feasible. Extraperitonealized anastomosis and pelvic drainage obtained a relatively low rate of AL and avoided unnecessary functional stomas. Pelvic irrigation-suction-drainage was an effective procedure to resolve AL, and functional stoma was potentially used as a salvage modality for serious leakage.

Transanal minimally invasive surgery to rescue anastomosis following leak after low anterior resection: A case report

Restorative low anterior resection(LAR)for rectal cancer carries a significant risk of anastomotic leak:One of the most feared complications in colorectal surgery.Operative management may include takedown of the anastomosis and end colostomy which,in some cases,is permanent.Other contemporary operative measures include over the scope clips and Endosponge.Recently,there have been case reports and a Society of American Endoscopic and Gastrointestinal Surgeons video on the novel use of transanal minimally invasive surgery(TAMIS)in the management of anastomotic leak.We present a 59-year-old female who underwent LAR after declining radiotherapy for a bulky 9 cm rectal tumour 9-10 cm from the anal verge.Following clinical deterioration,computed tomography demonstrated an anastomotic leak communicating with a 5-cm pelvic collection containing gas.At laparoscopy,pus and faeculent material were washed from the pelvic cavity and drains were placed.Intra-operative endoscopy demonstrated a 7-8 mm dehiscence at the anastomosis.The defect(approximately 7 cm from the anal verge)was successfully closed using TAMIS and a running V-lock suture.The patient recovered well and was discharged home on post-operative day 20.In this case,a low colorectal anastomotic leak was successfully rescued with TAMIS.This novel technique may be useful in the armamentarium of colorectal surgeons experienced in TAMIS.

Assessment and management of low anterior resection syndrome after sphincter preserving surgery for rectal cancer

Many patients develop a variety of bowel dysfunction after sphincter preserving surgeries(SPS)for rectal cancer.The bowel dysfunction usually manifests in the form of low anterior resection syndrome(LARS),which has a negative impact on the patients'quality of life.This study reviewed the LARS after SPS,its mechanism,risk factors,diagnosis,prevention,and treatment based on previously published studies.Adequate history taking,physical examination of the patients,using validated questionnaires and other diagnostic tools are important for assessment of LARS severity.Treatment of LARS should be tailored to each patient.Multimodal therapy is usually needed for patients with major LARS with acceptable results.The treatment includes conservative management in the form of medical,pelvic floor rehabilitation and transanal irrigation and invasive procedures including neuromodulation.If this treatment failed,fecal diversion may be needed.In conclusion,Initial meticulous dissection with preservation of nerves and creation of a neorectal reservoir during anastomosis and proper Kegel exercise of the anal sphincter can minimize the occurrence of LARS.Pre-treatment counseling is an essential step for patients who have risk factors for developing LARS.

Sphincter-preserving R0 total mesorectal excision with resection of internal genitalia combined with pre-or postoperative chemoradiation for T4 rectal cancer in females

AIM: To evaluate the impact of chemoradiation admi- nistered pre- or postoperatively on prognosis in females following R0 extended resection with sphincter- preserving total mesorectal excision (TME) for locally advanced rectal cancer and to assess the association between chemoradiation and intra- and postoperative variables. METHODS: Twenty-one females were treated for locally advanced but preoperatively assessed as primarily resectable rectal cancer involving reproductive organs. Anterior resection with TME and excision of internal genitalia was combined with neo- or adjuvant chemoradiation. Two-year disease-free survival analysis was performed with the Kaplan-Meier method and log- rank test. The association between chemoradiation and other variables was evaluated with the Fisher’s exact test and Mann-Whitney test. RESULTS: Survival rate decreased in anaemic females (51.5% vs 57.4%), in patients older than 60 years (41.8% vs 66.7%) with poorly differentiated cancers (50.0% vs 55.6%) and tumors located ≤ 7 cm from the anal verge (42.9% vs 68.1%) but with the lack of importance. Patients with negative lymph nodes and women chemoradiated preoperatively had significantly favourable prognosis (85.7% vs 35.7%; P= 0.03 and 80.0% vs 27.3%; P = 0.01, respectively). Preoperative chemoradiation compared to adjuvant radiochemotherapy was not significantly associated with the duration of surgery, incidence of intraoperative bowel perforation and blood loss ≥ 1 L, rate of postoperative bladder and anorectal dysfunction, and minimal distal resection margin. It significantly influenced minimal radial margin (mean 4.2 mm vs 1.1 mm; P < 0.01). CONCLUSION: Despite involving internal genitalia, long-term disease-free survival and sphincter preservation may be achieved with combined-modality therapy for females with T4 locally advanced rectal carcinoma. Neoadjuvant chemoradiation does not compromise functional results and may significantly improve oncological outcomes probably due to enhanced radial clearance.

Magnetic resonance imaging-based deep learning model to predict multiple firings in double-stapled colorectal anastomosis

BACKGROUND Multiple linear stapler firings during double stapling technique(DST)after laparoscopic low anterior resection(LAR)are associated with an increased risk of anastomotic leakage(AL).However,it is difficult to predict preoperatively the need for multiple linear stapler cartridges during DST anastomosis.AIM To develop a deep learning model to predict multiple firings during DST anastomosis based on pelvic magnetic resonance imaging(MRI).METHODS We collected 9476 MR images from 328 mid-low rectal cancer patients undergoing LAR with DST anastomosis,which were randomly divided into a training set(n=260)and testing set(n=68).Binary logistic regression was adopted to create a clinical model using six factors.The sequence of fast spin-echo T2-weighted MRI of the entire pelvis was segmented and analyzed.Pure-image and clinical-image integrated deep learning models were constructed using the mask region-based convolutional neural network segmentation tool and three-dimensional convolutional networks.Sensitivity,specificity,accuracy,positive predictive value(PPV),and area under the receiver operating characteristic curve(AUC)was calculated for each model.RESULTS The prevalence of≥3 linear stapler cartridges was 17.7%(58/328).The prevalence of AL was statistically significantly higher in patients with≥3 cartridges compared to those with≤2 cartridges(25.0%vs 11.8%,P=0.018).Preoperative carcinoembryonic antigen level>5 ng/mL(OR=2.11,95%CI 1.08-4.12,P=0.028)and tumor size≥5 cm(OR=3.57,95%CI 1.61-7.89,P=0.002)were recognized as independent risk factors for use of≥3 linear stapler cartridges.Diagnostic performance was better with the integrated model(accuracy=94.1%,PPV=87.5%,and AUC=0.88)compared with the clinical model(accuracy=86.7%,PPV=38.9%,and AUC=0.72)and the image model(accuracy=91.2%,PPV=83.3%,and AUC=0.81).CONCLUSION MRI-based deep learning model can predict the use of≥3 linear stapler cartridges during DST anastomosis in laparoscopic LAR surgery.This model might help determine the best anastomosis strategy by avoiding DST when there is a high probability of the need for≥3 linear stapler cartridges.

Systematic review of oncological outcomes following laparoscopic vs open total mesorectal excision

AIM: To systematically analyze the randomized trials comparing the oncological and clinical effectiveness of laparoscopic total mesorectal excision(LTME) vs open total mesorectal excision(OTME) in the management of rectal cancer.METHODS: Published randomized, controlled trials comparing the oncological and clinical effectiveness of LTME vs OTME in the management of rectal cancer were retrieved from the standard electronic medical databases. The data of included randomized, controlled trials was extracted and then analyzed according to the principles of meta-analysis using RevMan? statistical software. The combined outcome of the binary variables was expressed as odds ratio(OR) and the combined outcome of the continuous variables waspresented in the form of standardized mean difference(SMD). RESULTS: Data from eleven randomized, controlled trials on 2143 patients were retrieved from the electronic databases. There was a trend towards the higher risk of surgical site infection(OR = 0.66; 95%CI: 0.44-1.00; z = 1.94; P < 0.05), higher risk of incomplete total mesorectal resection(OR = 0.62; 95%CI: 0.43-0.91; z = 2.49; P < 0.01) and prolonged length of hospital stay(SMD,-1.59; 95%CI:-0.86--0.25; z = 4.22; P < 0.00001) following OTME. However, the oncological outcomes like number of harvested lymph nodes, tumour recurrence and risk of positive resection margins were statistically similar in both groups. In addition, the clinical outcomes such as operative complications, anastomotic leak and all-cause mortality were comparable between both approaches of mesorectal excision.CONCLUSION: LTME appears to have clinically and oncologically measurable advantages over OTME in patients with primary rectal cancer in both short term and long term follow ups.

Iatrogenic colorectal perforation induced by anorectal manometry:Report of two cases after restorative proctectomy for distal rectal cancer

There are no reports regarding perforation of the colorectum induced by anorectal manometry. We report two cases of colorectal perforation that occurred during manometry in the patients undergoing restorative proctectomy for distal rectal cancer. In the first patient, computed tomography showed an extraperitoneal perforation in the pelvic cavity and a rupture of the rectal wall. A localized perforation into the retroperitoneum was managed conservatively. In the second patient, a 3 cm linear colon rupture was detected above the anastomotic site. A primary closure of the perforated colon and proximal ileostomy were conducted, but the patient died 2 wk later. We hypothesize that the perforation induced by anorectal manometry may be associated with the relative weakening of the proximal bowel wall due to anastomosis, decreased compliance, and abnormal rectal sensation. We suggest that measurement of the maximum tolerable volume should not be routinely performed alter restorative proctectomy for distal rectal cancer.

Anastomotic leakage in rectal cancer surgery:Retrospective analysis of risk factors

BACKGROUND Anastomotic leakage(AL)after restorative surgery for rectal cancer(RC)is associated with significant morbidity and mortality.AIM To ascertain the risk factors by examining cases of AL in rectal surgery in this retrospective cohort study.METHODS To identify risk factors for AL,a review of 583 patients who underwent rectal resection with a double-stapling colorectal anastomosis between January 2007 and January 2022 was performed.Clinical,demographic and operative features,intraoperative outcomes and oncological characteristics were evaluated.RESULTS The incidence of AL was 10.4%,with a mean time interval of 6.2±2.1 d.Overall mortality was 0.8%.Mortality was higher in patients with AL(4.9%)than in patients without leak(0.4%,P=0.009).Poor bowel preparation,blood transfusion,median age,prognostic nutritional index<40 points,tumor diameter and intraoperative blood loss were identified as risk factors for AL.Location of anastomosis,number of stapler cartridges used to divide the rectum,diameter of circular stapler,level of vascular section,T and N status and stage of disease were also correlated to AL in our patients.The diverting ileostomy did not reduce the leak rate,while the use of the transanastomic tube significantly did.CONCLUSION Clinical,surgical and pathological factors are associated with an increased risk of AL.It adversely affects the morbidity and mortality of RC patients.