Resection For Mid-low Rectal Cancer Research Articles

Prediction of symptomatic anastomotic leak after rectal cancer surgery: A machine learning approach.

Anastomotic leakage (AL) remains the most dreaded and unpredictable major complication after low anterior resection for mid-low rectal cancer. The aim of this study is to identify patients with high risk for AL based on the machine learning method. Patients with mid-low rectal cancer undergoing low anterior resection were enrolled from West China Hospital between January 2008 and October 2019 and were split by time into training cohort and validation cohort. The least absolute shrinkage and selection operator (LASSO) method and stepwise method were applied for variable selection and predictive model building in the training cohort. The area under the receiver operating characteristic curve (AUC) and calibration curves were used to evaluate the performance of the models. The rate of AL was 5.8% (38/652) and 7.2% (15/208) in the training cohort and validation cohort, respectively. The LASSO-logistic model selected almost the same variables (hypertension, operating time, cT4, tumor location, intraoperative blood loss) compared to the stepwise logistic model except for tumor size (the LASSO-logistic model) and AmericanSociety of Anesthesiologists score (the stepwise logistic model). The predictive performance of the LASSO-logistics model was better than the stepwise-logistics model (AUC: 0.790 vs. 0.759). Calibration curves showed mean absolute error of 0.006 and 0.013 for the LASSO-logistics model and stepwise-logistics model, respectively. Our study developed a feasible predictive model with a machine-learning algorithm to classify patients with a high risk of AL, which would assist surgical decision-making and reduce unnecessary stoma diversion. The involved machine learning algorithms provide clinicians with an innovative alternative to enhance clinical management.

The impact of anastomotic leak on long-term oncological outcomes after low anterior resection for mid-low rectal cancer: extended follow-up of a randomised controlled trial

PurposeThe impact of anastomotic leaks (AL) on oncological outcomes after low anterior resection for mid-low rectal cancer is still debated. The aim of this study was to evaluate overall survival (OS), disease-free survival (DFS), and local and distant recurrence in patients with AL following low anterior resection.MethodsThis is an extension of a multicentre RCT (NCT01110798). Kaplan–Meier method and the log-rank test were used to estimate and compare the 3-, 5-, and 10-year OS and DFS, and local and distant recurrence in patients with and without AL. Predictors of OS and DFS were evaluated using the Cox regression analysis as secondary aim.ResultsFollow-up was available for 311 patients. Of them, 252 (81.0%) underwent neoadjuvant chemoradiotherapy and 138 (44.3%) adjuvant therapy. AL occurred in 63 (20.3%) patients. At a mean follow-up of 69.5 ± 31.9 months, 23 (7.4%) patients experienced local recurrence and 49 (15.8%) distant recurrence. The 3-, 5-, and 10-year OS and DFS were 89.2%, 85.3%, and 70.2%; and 80.7%, 75.1%, and 63.5% in patients with AL, and 88.9%, 79.8% and 72.3%; and 83.7, 74.2 and 62.8%, respectively in patients without (p = 0.89 and p = 0.84, respectively). At multivariable analysis, AL was not an independent predictor of OS (HR 0.65, 95%CI 0.34–1.28) and DFS (HR 0.70, 95%CI 0.39–1.25), whereas positive circumferential resection margins and pathological stage impaired both.ConclusionsIn the context of modern multimodal rectal cancer treatment, AL does not affect long-term OS, DFS, and local and distant recurrence in patients with mid-low rectal cancer.

Transanal Drainage Tube Use for Preventing Anastomotic Leakage After Laparoscopic Low Anterior Resection in Patients With Rectal Cancer

Preventing anastomotic leakage (AL) is crucial for colorectal surgery. Some studies have suggested a positive role of transanal drainage tubes (TDTs) in AL prevention after low anterior resection, but this finding is controversial. To assess the effect of TDTs in AL prevention after laparoscopic low anterior resection for rectal cancer. This multicenter randomized clinical trial with parallel groups (TDT vs non-TDT) was performed from February 26, 2016, to September 30, 2020. Participants included patients from 7 different hospitals in China who were undergoing laparoscopic low anterior resection with the double-stapling technique for mid-low rectal cancer; 576 patients were initially enrolled in this study, and 16 were later excluded. Ultimately, 560 patients were randomly divided between the TDT and non-TDT groups. A silicone tube was inserted through the anus, and the tip of the tube was placed approximately 5 cm above the anastomosis under laparoscopy at the conclusion of surgery. The tube was fixed with a skin suture and connected to a drainage bag. The TDT was scheduled for removal 3 to 7 days after surgery. The primary end point was the postoperative AL rate within 30 days. In total, 576 patients were initially enrolled in this study; 16 of these patients were excluded. Ultimately, 560 patients were randomly divided between the TDT group (n = 280; median age, 61.5 years [IQR, 54.0-68.8 years]; 177 men [63.2%]) and the non-TDT group (n = 280; median age, 62.0 years [IQR, 52.0-69.0 years]; 169 men [60.4%]). Intention-to-treat analysis showed no significant difference between the TDT and non-TDT groups in AL rates (18 [6.4%] vs 19 [6.8%]; relative risk, 0.947; 95% CI, 0.508-1.766; P = .87) or AL grades (grade B, 14 [5.0%] and grade C, 4 [1.4%] vs grade B, 11 [3.9%] and grade C, 8 [2.9%]; P = .43). In the stratified analysis based on diverting stomas, there was no significant difference in the AL rate between the groups, regardless of whether a diverting stoma was present (without stoma, 12 [5.8%] vs 15 [7.9%], P = .41; and with stoma, 6 [8.3%] vs 4 [4.5%], P = .50). Anal pain was the most common complaint from patients in the TDT group (130 of 280, 46.4%). Accidental early TDT removal occurred in 20 patients (7.1%), and no bleeding or iatrogenic colonic perforations were detected. The results from this randomized clinical trial indicated that TDTs may not confer any benefit for AL prevention in patients who undergo laparoscopic low anterior resection for mid-low rectal cancer without preoperative radiotherapy. ClinicalTrials.gov Identifier: NCT02686567.

Analysis on short-term efficacy of reduced-port laparoscopic anterior resection for mid-low rectal cancer

Analysis on short-term efficacy of reduced-port laparoscopic anterior resection for mid-low rectal cancer

Chinese expert consensus on the diagnosis and treatment for lateral lymph node metastasis of rectal cancer (2019 edition)

Lateral lymph node metastasis represents a major cause of local pelvic recurrence after curative resection for mid-low rectal cancer. Considerable controversies over issues remain among eastern and western countries, with respect to the diagnosis of lateral lymph node metastasis, the multidisciplinary management regime, indication for lateral pelvic lymph node dissection, and the prognosis of surgical dissection. The purpose of this expert consensus is to improve the understanding of this condition among Chinese specialists, and to help standardizing the diagnosis and therapeutic strategies for lateral lymph node metastasis. Each statement and recommendation in this consensus were generated based on suggestions from at least three experts, agreed by a majority of experts from the Chinese expert panel. The evaluation criteria by U.S. Preventive Services Task Force was adopted for the grading of recommendations. In respect to the aforementioned controversies, the present consensus produced 21 statements on diagnosis and treatment for lateral lymph node metastasis. The pending issues in this consensus need further high-quality clinical practice and research.

Reconsideration of the Anterior Surgical Plane of Total Mesorectal Excision for Rectal Cancer.

Previous studies on total mesorectal excision suggested dissection anterior to Denonvilliers' fascia, which might lead to intraoperative pelvic autonomic nerves injury and a high incidence of urogenital dysfunction. We dissected 4 cases of cadavers, mainly focusing on anatomy of Denonvilliers' fascia, to study the relationship between Denonvilliers' fascia and rectum. In practice, instead of dissection 1 cm above peritoneal reflection, dissection of the peritoneum was performed at the lowest level of peritoneal reflection during laparoscopic resection for mid-low rectal cancer. The cadaveric study revealed that there were loose tissues between Denonvilliers' fascia and rectal specimen, thus a surgical plane posterior to Denonvilliers' fascia did exist. During laparoscopic resection for mid-low rectal cancer, some loose reticulate structures between Denonvilliers' fascia and proper fascia of rectum would present after dissection of peritoneum at the lowest level of peritoneal reflection. Then dissection within the surgical plane posterior to Denonvilliers' fascia became easy and feasible. In this plane, both the pelvic nerves and postoperative urogenital function could be well protected by Denonvilliers' fascia. The anterior surgical plane for total mesorectal excision should be reconsidered, and dissection posterior to Denonvilliers' fascia is feasible and practicable for patients without risk of positive anterior circumferential resection margin.

Effect of preservation of Denonvilliers' fascia during laparoscopic resection for mid-low rectal cancer on protection of male urinary and sexual functions.

The aim of this study was to investigate the effect of preservation of Denonvilliers’ fascia (DF) during laparoscopic resection for mid-low rectal cancer on protection of male urogenital function. Whether preservation of DF during TME is effective for protection of urogenital function is largely elusive.Seventy-four cases of male mid-low rectal cancer were included. Radical laparoscopic proctectomy was performed, containing 38 cases of preservation of DF (P-group) and 36 cases of resection of DF (R-group) intraoperatively. Intraoperative electrical nerve stimulation (INS) on pelvic autonomic nerve was performed and intravesical pressure was measured manometrically. Urinary function was evaluated by residual urine volume (RUV), International Prostatic Symptom Score (IPSS), and quality of life (QoL). Sexual function was evaluated using the International Index of Erectile Function (IIEF) scale and ejaculation function classification.Compared with performing INS on the surfaces of prostate and seminal vesicles in the R-group, INS on DF in the P-group exhibited higher increasing intravesical pressure (7.3 ± 1.5 vs 5.9 ± 2.4 cmH2O, P = 0.008). In addtion, the P-group exhibited lower RUV (34.3 ± 27.2 vs 57.1 ± 50.7 mL, P = 0.020), lower IPSS and QoL scores (7 days: 6.1 ± 2.4 vs 9.5 ± 5.9, P = 0.002 and 2.2 ± 1.1 vs 2.9 ± 1.1, P = 0.005; 1 month: 5.1 ± 2.4 vs 6.6 ± 2.2, P = 0.006 and 1.6 ± 0.7 vs 2.1 ± 0.6, P = 0.003, respectively), higher IIEF score (3 months: 10.7 ± 2.1 vs 8.9 ± 2.0, P = 0.000; 6 months: 14.8 ± 2.2 vs 12.9 ± 2.2, P = 0.001) and lower incidence of ejaculation dysfunction (3 months: 28.9% vs 52.8%, P = 0.037; 6 months: 18.4% vs 44.4%, P = 0.016) postoperatively.Preservation of DF during laparoscopic resection for selective male mid-low rectal cancer is effective for protection of urogenital function.

Effect of preoperative injection of carbon nanoparticle suspension on the outcomes of selected patients with mid-low rectal cancer

BackgroundCarbon nanoparticles show significant lymphatic tropism and can be used to identify lymph nodes surrounding mid-low rectal tumors. In this study, we analyzed the effect of trans anal injection of a carbon nanoparticle suspension on the outcomes of patients with mid-low rectal cancer who underwent laparoscopic resection.MethodsWe collected the data of 87 patients with mid-low rectal cancer who underwent laparoscopic resection between November 2014 and March 2015 at Cancer Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College. For 35 patients in the experimental group, the carbon nanoparticle suspension was injected transanally into the submucosa of the rectum around the tumor 30 min before the operation; 52 patients in the control group underwent the operation directly without the injection of carbon nanoparticle suspension. We then compared the operation outcomes between the two groups.ResultsIn the experimental group, the rate of incomplete mesorectal excision was lower than that in the control group, but no significant difference was found (2.9% vs. 7.7%, P = 0.342). The distance between the tumor and the circumferential resection margin was 5.8 ± 1.4 mm in the experimental group and 4.8 ± 1.1 mm in the control group (P = 0.001). The mean number of lymph nodes removed was 28.2 ± 9.4 in the experimental group and 22.7 ± 7.3 in the control group (P = 0.003); the mean number of lymph nodes smaller than 5 mm in diameter was 10.1 ± 7.5 and 4.5 ± 3.7, respectively (P < 0.001). Three patients in the experimental group received lateral lymph node resection. Among the three patients, we retrieved three nodes (one stained node) from the first patient, three nodes (two stained nodes) from the second patient, and two nodes (no stained nodes) from the third patient.ConclusionsInjecting a carbon nanoparticle suspension improved the outcomes of patients who underwent laparoscopic resection for mid-low rectal cancer; it also improved the accuracy of pathologic staging. Moreover, for selected patients, this technique narrowed the scope of lateral lymph node dissection.

Factors affecting operating time in laparoscopic anterior resection of rectal cancer

BackgroundThe objective of this study is to clarify the relationship between demographic and surgical factors and operating time, and thus operative difficulty, in patients undergoing laparoscopic anterior resection for mid-low rectal cancer, since different studies have derived different results.MethodsThe records of patients with mid-low rectal cancer who underwent laparoscopic anterior resection were retrospectively studied. Demographic data, tumor characteristics, and pelvimetry measurements were collected and analyzed with respect to operating time, using correlation coefficient analysis, principle component analysis, and linear regression.ResultsA total of 14 patients (10 males, 4 females; 65.50 ± 7.12 years of age) were included. Demographic and tumor characteristics not correlated with operating time. Body mass index (BMI) (P = 0.001); interacetabular distance (IA) (P = 0.001); anatomical transverse distance (IP) (P = 0.008); interischial distance (IS) (P = 0.002); intertuberous distance (IT) (P = 0.005); distance between the coccyx and symphysis (CoSy) (P = 0.013); and the angle of the lower border of the symphysis pubis, upper border of symphysis pubis, and sacral promontory (angle 5) (P = 0.004) were significantly associated with operating time. The equation was:operatingtime=0.653×BMI+0.818×angle5-0.404×IA-0.380×IP-0.512×IS-0.405×IT-0.570×CoSy+330.8.ConclusionsTransverse diameters of the pelvis, BMI, angle 5, and CoSy played the most important role in affecting operating time. The equation can be a very useful tool for preoperative assessment.

Contributing Factors on Lymph Node Yield after Surgery for Mid-Low Rectal Cancer

PurposeThe purpose of the present study was to evaluate the contributing factors to the lymph node status as well as to define the impact of preoperative concurrent chemoradiotherapy (CCRT) on the number of lymph nodes retrieved in mid-low rectal cancer.Materials and MethodsWe retrospectively analyzed 277 patients who underwent curative surgical resection for mid-low rectal cancer between 1998 and 2007. Eighty-two patients received long course preoperative CCRT followed by surgery.ResultsA mean of 13.12±9.28 lymph nodes was retrieved. In a univariate analysis, distance from the anal verge, pT stage, pN stage, lymphovascular invasion, preoperative CCRT had significant influence on the number of lymph nodes retrieved. In a multivariate model, patients in the CCRT group had fewer retrieved lymph nodes than the non-CCRT group (p<0.001). Both univariate and multivariate analyses showed that the ypN0 group had fewer retrieved lymph nodes than the ypN1-2 group (p=0.027) in the CCRT group.ConclusionPreoperative CCRT was an independent risk factor for failure to harvest an appropriate number of lymph nodes, and node-negative patients who received CCRT had fewer lymph nodes harvested.

Lack of prognostic role of pre- and postoperative peritoneal cytology and cytokeratin PCR-expression on local recurrence after curative anterior resection for mid-low rectal cancer

Local recurrence continues to be a major problem in rectal cancer. After cancer removal, detection of viable cancer cells could be useful to identify patients at risk for local recurrence. Thus, aim of the study was the detection of residual peritoneal cancer cells with a possible prognostic role for local recurrence. Twenty-nine patients were operated (R0) for low (extraperitoneal) rectal cancer, without neoadjuvant radiochemotherapy. Before and immediately after cancer removal, a peritoneal lavage was done to evaluate by RT-PCR the cytokeratin 20 mRNA on isolated cells and in order to detect cancer cells by the Thin-prep test. After a median follow-up of 39months, 5 patients died (17%), one for non-cancer-related disease, two (7%) for local recurrence and peritoneal carcinosis, and two for distant metastases. Preoperative cytology with Thin-prep test was positive in 4 patients (14%), while postoperative peritoneal cytology was positive only in 1 patient, different from the previous. No patient developed local or distal recurrence and all were disease-free at the end of the follow-up. RT-PCR analysis was positive on the peritoneal lavage after cancer removal in 11 patients. One died for unrelated cause and no one developed local recurrences. Local recurrence occurred in only 1 of the 2 patients with positive RT-PCR analysis on the first lavage and negative on the second lavage. Our study demonstrates a not important prognostic role of Thin-prep test and RT-PCR of cytokeratin 20 mRNA on the detection of patients at risk for local recurrence after curative resection of rectal cancer.