Background and Objective: Anastomotic leakage is one of the most serious complications after laparoscopic low anterior resection Low Anterior Resection (LAR) for rectal cancers. The purpose of this study was to evaluate the effectiveness of a transanal drainage tube placed for the prevention of anastomotic leakage after laparoscopic LAR. Methods: The clinical data of 220 patients with rectal cancer who underwent laparoscopic LAR using the double stapling technique Double Stapling Department of Colorectal Surgery, National Cancer Center/National Clinical Research Center for Cancer/Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College Technique (DST) from Jun 2017 to Dec 2018 were analyzed retrospectively at our institution. A transanal drainage tube was placed after anastomosis in 120 patients (TDT group). Another 100 patients were operated on without a transanal drainage tube (NTDT group). Clinicopathological and surgical factors, the frequencies of anastomotic leakage and re-operation after leakage were compared between the two groups. Results: Patient age, gender, body mass index, American Society of Anesthesiologists (ASA) score, previous abdominal surgery, intraoperative blood loss, tumor size, tumor stage, specimen length, distance of tumor from the anal verge, and operative time were comparable between the two groups. Overall rate of leakage was 4.5% (10/220). The frequency of leakage was 3.3% (4/120) in TDT group and was 6.0% (6/100) in NTDT group. The rate of leakage was significantly lower in TDT group (p<0.05). Furthermore, the re-operation rate for symptomatic anastomotic leakage was 50.0% (2/4) in TDT group, while in contrast it was 83.3% (5/6) in NTDT group. The rate of re-operation was lower in TDT group than NTDT group (p<0.05). Conclusions: The use of a transanal drainage tube in laparoscopic LAR for rectal cancer is a simple and effective method for prevention of anastomotic leakage and decreases the rate of re-operation after symptomatic leakage.

Colorectal cancer (CRC) is a common malignant tumor of the digestive tract and lacks specific diagnostic markers. In this study, we utilized 10 public datasets from the NCBI Gene Expression Omnibus (NCBI-GEO) database to identify a set of significantly differentially expressed genes (DEGs) between tumor and control samples and WGCNA (Weighted Gene Co-Expression Network Analysis) to construct gene co-expression networks incorporating the DEGs from The Cancer Genome Atlas (TCGA) and then identify genes shared between the GEO datasets and key modules. Then, these genes were screened via MCC to identify 20 hub genes. We utilized regression analyses to develop a prognostic model and utilized the random forest method to validate. All hub genes had good diagnostic value for CRC, but only CLCA1 was related to prognosis. Thus, we explored the potential biological value of CLCA1. The results of gene set enrichment analysis (GSEA) and immune infiltration analysis showed that CLCA1 was closely related to tumor metabolism and immune invasion of CRC. These analysis results revealed that CLCA1 may be a candidate diagnostic and prognostic biomarker for CRC.

Selective lateral lymph node dissection after neoadjuvant chemoradiotherapy in rectal cancer

Original Article Perineural invasion is a prognostic factor in stage II colorectal cancer but not a treatment indicator for traditional chemotherapy: a retrospective cohort study Juan Li, Shiwen Mei, Sichen Zhou, Fuqiang Zhao, Qian Liu

Background: We aimed to analyze the benefit of adjuvant chemotherapy in high-risk stage II colon cancer patients and the impact of high-risk factors on the prognostic effect of adjuvant chemotherapy. Methods: This study is a multi-center, retrospective study, A total of 931 patients with stage II colon cancer who underwent curative surgery in 8 tertiary hospitals in China between 2016 and 2017 were enrolled in the study. Cox proportional hazard model was used to assess the risk factors of disease-free survival (DFS) and overall survival (OS) and to test the multiplicative interaction of pathological factors and adjuvant chemotherapy (ACT). The additive interaction was presented using the relative excess risk due to interaction (RERI). The Subpopulation Treatment Effect Pattern Plot (STEPP) was utilized to assess the interaction of continuous variables on the ACT effect. Results: A total of 931 stage II colon cancer patients were enrolled in this study, the median age was 63 years old (interquartile range: 54–72 years) and 565 (60.7%) patients were male. Younger patients (median age, 58 years vs 65 years; P < 0.001) and patients with the following high-risk features, such as T4 tumors (30.8% vs 7.8%; P < 0.001), grade 3 lesions (36.0% vs 22.7%; P < 0.001), lymphovascular invasion (22.1% vs 6.8%; P < 0.001) and perineural invasion (19.4% vs 13.6%; P = 0.031) were more likely to receive ACT. Patients with perineural invasion showed a worse OS and marginally worse DFS (hazardous ratio [HR] 2.166, 95% confidence interval [CI] 1.282–3.660, P = 0.004; HR 1.583, 95% CI 0.985–2.545, P = 0.058, respectively). Computing the interaction on a multiplicative and additive scale revealed that there was a significant interaction between PNI and ACT in terms of DFS (HR for multiplicative interaction 0.196, p = 0.038; RERI, -1.996; 95%CI, -3.600 to -0.392) and OS (HR for multiplicative interaction 0.112, p = 0.042; RERI, -2.842; 95%CI, -4.959 to -0.725). Conclusions: Perineural invasion had prognostic value, and it could also influence the effect of ACT after curative surgery. However, other high-risk features showed no implication of efficacy for ACT in our study. Trial registration: This study is registered on ClinicalTrials.gov, NCT03794193 (04/01/2019).

Nomograms and risk score models for predicting survival in rectal cancer patients with neoadjuvant therapy