Upregulated NLGN1 predicts poor survival in colorectal cancer

Background

Neuroligin1 (NLGN1) is a main component of excitatory glutamatergic synapses complex and is important for synapse assembly and function. The clinical value of NLGN1 in colorectal cancer (CRC) is not clear.

Methods

We obtained the expression data of 1143 CRC patients from 3 independent Gene Expression Omnibus (GEO) datasets (GSE32323, GSE24551, GSE39582) and The Cancer Genome Atlas (TCGA) to make the comparison of the NLGN1 expression level between CRC tissues and matched noncancerous tissues, and to evaluate its value in predicting survival of CRC patients. At the protein level, these results were further confirmed by immunohistochemical staining of 52 CRC samples in our own centre. Finally, the function of NLGN1 was explored by gene set enrichment analysis (GSEA).

Results

Increased mRNA and protein levels of NLGN1 expression were associated with worse overall survival or recurrence-free survival in CRC patients from 2 GEO datasets, the TCGA database, and our cohort. In addition, multivariate regression analysis showed that NLGN1 was an independent poor prognostic factor of survival in patients with CRC in TCGA database (OR = 2.524, P = 0.010). Functional analysis revealed that NLGN1 was correlated with function involving the Hedgehog signaling pathway, mismatch repair process, and some material metabolism processes.

Conclusions

This study is the first to implicate and verify NLGN1 as a new poor prognostic marker for CRC.

[Anatomical observation of the left parietal peritoneum and its clinical significance in left retro-mesocolic space dissection]

Objective: To investigate the anatomic characteristics of the left parietal peritoneum and its surgical implementation while dissecting in left retro-mesocolic space. Methods: A descriptive case series research methods was used. (1) surgical videos of 35 patients who underwent laparoscopic radical resection (complete mobilization of splenic flexure) of colorectal cancer in Union Hospital of Fujian Medical University between January 2018 and December 2018 were reviewed; (2) four specimens after radical resection of rectal cancer performing in June 2020 were prospectively enrolled and reviewed; (3) five specimens of left parietal peritoneum from 5 cadaveric abdomen (3 males and 2 females) were enrolled and reviewed as well; Tissues of 3 unseparated regions, namely the root of the inferior mesenteric artery (IMA), the medial region and the lateral region (including kidney tissue), from above the 5 cadaveric abdominal specimens were selected to perform Masson staining and histopathological examination. Results: (1) Surgical video observation: "Staggered layer phenomenon" and typical left parietal peritoneum was found in 77.1% (27/35) of patients when the left retro-mesocolic space was separated from the lateral and central approaches. The left parietal peritoneum presented as a rigid fascia barrier between the lateral and central approaches, which was a translucent dense connective tissue fascia. After the splenic flexure were completely mobilized, the left parietal peritoneum stump continued to the cephalic side. (2) Observation of 4 surgical specimens: The dorsal side of the left mesocolon specimen was studied, and the left parietal peritoneum stump edge was identified. The outside of the stump edge was the left hemicolon dorsal layer, which was continuously downward to the rectal fascia propria. (3) Cadaveric abdominal specimens: The left retro-mesocolic space was separated through lateral and central approaches, and the rigid fascia barrier, essentially the left parietal peritoneum and Gerota fascia, was encountered. Cross-section view showed that the left parietal peritoneum could be further detached from the dorsal layer of the left mesocolon from the outside, but could not be further detached from the inside out. (4) Histological examination: There was no obvious fascia structure in the IMA root region, while outside the IMA root region, the left bundle of inferior mesenteric plexus penetrating Gerota fascia was observed. There were 4 layers of fascias in the medial region, including the ventral layer of the left mesocolon, the dorsal layer of the left mesocolon, left parietal peritoneum and Gerota fascia. Small vessels were observed between the dorsal layer of the left mesocolon and the left parietal peritoneum. In lateral region, renal tissue and renal fascia were observed. Three layers of fascia structures were observed clearly under high power field, including the dorsal layer of the left mesocolon, left parietal peritoneum, and Gerota fascia. Conclusions: The left parietal peritoneum is the anatomical basis of the "staggered layer phenomenon" from the lateral or central approaches during the separation of left retro-mesocolic space. The small vessels in the dissection plane are the anatomical basis of intraoperative microbleeding, which need pre-coagulation. The central part of Gerota fascia is penetrated by the branches of the inferior mesenteric plexus, which results in a relatively dense surgical plane. Thus, during the dissection through the central approach, it is easy to involve in wrong surgical plane by deeper dissection.

A nomogram predicting the difficulty of laparoscopic surgery for rectal cancer

PURPOSE

This study aimed to identify the risk factors associated with performing a difficult laparoscopic radical resection of rectal cancer, and to establish a predictive nomogram to help individual clinical treatment decisions.

METHODS

A total of 977 patients with rectal cancer who underwent laparoscopic radical resection between January 2014 and December 2016 were enrolled in this study. The difficulty of laparoscopic-assisted rectal resection (LARR) was defined according to the scoring criteria reported by Escal. A logistic regression analysis was performed to identify the variables that may affect the difficulty of LARR, and a nomogram predicting the surgical difficulty was created.

RESULTS

A multivariate analysis demonstrated that a BMI > 28 kg/m², the distance between the tumor and the anal margin ≤ 5 cm, the maximum transverse tumor diameter > 3 cm tumor, interspinous distance < 10 cm, history of abdominal surgery, and preoperative radiotherapy were independent risk factors and they were, therefore, included in the predictive nomogram for identifying a difficult LARR.

CONCLUSIONS

This study defined a difficult LARR and identified independent risk factors for a difficult operation and created a predictive nomogram for difficult LARR. This nomogram may facilitate the stratification of patients at risk for being associated with a difficult LARR for rectal cancer.

An Intrasheath Separation Technique for Nerve-Sparing High Ligation of the Inferior Mesenteric Artery in Colorectal Cancer Surgery

Purpose

To investigate the relationship between the left trunk of the inferior mesenteric plexus (IMP) and the vascular sheath of the inferior mesenteric artery (IMA) and to explore anatomical evidence for autonomic nerve preservation during high ligation of the IMA in colorectal cancer surgery.

Methods

We evaluated the relationship in 23 consecutive cases of laparoscopic or robotic colorectal surgery with high ligation of the IMA at our institute. Anatomical dissection was performed on 5 formalin-fixed abdominal specimens. A novel anatomical evidence-based operative technique was proposed.

Results

Anatomical observation showed that the left trunk of the IMP was closely connected with the IMA and was involved in the composition of the vascular sheath. Based on anatomical evidence, we present a novel operative technique for nerve-sparing high ligation of the IMA that was successfully performed in 45 colorectal cancer surgeries with no intraoperative complications and satisfactory postoperative urogenital functional outcomes.

Conclusion

The left trunk of the IMP is involved in the composition of the IMA vascular sheath. This novel anatomical evidence-based operative technique for nerve-sparing high ligation of the IMA is technically safe and feasible.

Individualized conditional survival nomograms for patients with locally advanced rectal cancer treated with neoadjuvant chemoradiotherapy and radical surgery

BACKGROUND

Conditional survival (CS) considers the time already survived after surgery when estimating the survival probability, which may provide further useful prognostic information.

OBJECTIVE

To evaluate CS in patients with locally advanced rectal cancer (LARC) treated with neoadjuvant chemoradiotherapy (nCRT) and to create CS nomograms predicting the conditional probability of survival after proctectomy.

METHODS

Consecutive patients with LARC who received nCRT followed by radical resection between 2011 and 2016 were identified. CS was defined as the probability of surviving y years after already surviving for x years. The formula used for CS was CS(x|y) = S(x + y)/S(x), where S(x) represents the survival at x years. Nomograms were constructed to predict the 5-year conditional overall survival (cOS) and conditional recurrence-free survival (cRFS).

RESULTS

A total of 785 patients were included. The median follow-up time was 65.5 months. The probability of achieving 5-year survival after surgery for cancer increases with additional survival time. Maximum tumor diameter, distance from the anal verge, preoperative CA19-9 level, ypTNM stage and perineural invasion were independent predictors of OS, while maximum tumor diameter, distance from the anal verge, ypTNM stage and perineural invasion were independent risk factors for RFS. The nomograms predicted 5-year cOS and cRFS using these predictors and the time already survived. The online calculator can be accessed at http://www.rectalcancer.top/webcalculator.

CONCLUSION

The proposed nomograms predict survival in patients after surgery, taking the time already survived into account.

[Robotic versus laparoscopic total mesorectal excision with partial preservation of Denonvilliers fascia: a comparative study of short-term efficacy and urinary and erectile function]

Objective: Postoperative sexual and urinary dysfunctions are common in rectal cancer patients. This study was conducted to compare the short-term efficacy and the impact of surgery on urinary and erectile functions between laparoscopy and robotic-assisted total mesorectal excision (TME) with partial preservation of Denonvilliers fascia. Methods: A retrospective cohort study was carried out. Clinical data of 276 patients with low rectal cancer who underwent TME with partial preservation of Denonvilliers fascia in our department between January 2016 and March 2019, including 143 in robotic group and 133 in laparoscopic group, were analyzed. All the patients were positioned by rigid rectoscope, and the distance between the tumor and the anal verge was ≤7 cm. The urinary and erectile functions were followed up at postoperative 12-month and evaluated by IPSS score (0-7 points as mild symptoms, 8-19 points as moderate symptoms, 20-35 points as severe symptoms; the excellent rate was defined as the rate of mild symptoms) and IIEF-5 score (score ≥ 22 as no dysfunction, 12-21 as mild, 8-11 as moderate, and 5-7 as severe) respectively. Results: There were no significant differences in operation ways between the two groups (P>0.05). The operation time of the robotic group was longer than that of the laparoscopic group [(312.5±75.4) minutes vs. (273.9±65.6) minutes, t=4.514, P<0.001]. However, in patients with higher body mass index (BMI ≥25 kg/m(2)), there was no significant difference in operation time between the two groups [(309.3±78.5) minutes vs. (276.1±75.3) minutes, t=1.751, P=0.085]. The time to postoperative flatus [(1.3±0.4) days vs. (1.5±1.0) days, t=-2.037, P=0.046], defecation [1 (1-5) days vs. 1 (1-12) days, Z=-2.209, P=0.008] and liquid diet [(1.0±0.1) days vs. (1.2±0.1) days, t=3.195, P=0.002] in the robotic group were all shorter than those in the laparoscopic group. While postoperative length of hospital stay in the robotic group was longer than that in the laparoscopic group [(8.5±5.5) days vs. (7.2±3.3) days, t=2.419, P=0.016]. There were no significant differences between the two groups in intraoperative blood loss, conversion rate, morbidity of postoperative complications, positive rate of distal resection margin, positive rate of circumferential resection margin, and the number of resected lymph nodes (all P>0.05). At postoperative 12 months, none of the robotic group nor the laparoscopic group had severe urinary dysfunction, and the overall excellent rate of urinary function reached 97.6% (83/85) and 98.4% (61/62) respectively. The rate of normal and mild erectile dysfunction in the robotic group and the laparoscopic group were 92.2% (47/51) and 92.6% (38/41) respectively (P>0.05). There was no significant difference between the two groups was found regarding the urinary and erectile function (both P>0.05). Conclusions: Compared with laparoscopic, the robotic TME with partial preservation of Denonvilliers fascia has no significant differences in surgical safety and short-term efficacy. They have similar advantages in the protection of urinary and erectile function. Meanwhile the robotic surgery presents faster postoperative recovery of gastrointestinal function.

Pelvimetric and Nutritional Factors Predicting Surgical Difficulty in Laparoscopic Resection for Rectal Cancer Following Preoperative Chemoradiotherapy

AIM

Laparoscopic total mesorectal excision (LaTME) following preoperative chemoradiotherapy (PCRT) in locally advanced rectal cancer (LARC) is technically demanding. The present study is intended to evaluate predictive factors of surgical difficulty of LaTME following PCRT by using pelvimetric and nutritional factors.

METHOD

Consecutive LARC patients receiving LaTME after PCRT were included. Surgical difficulty was classified based upon intraoperative (operation time, blood loss, and conversion) and postoperative outcomes (postoperative hospital stay and morbidities). Pelvimetry was performed using preoperative T2-weighted MRI. Nutritional factors such as albumin-to-globulin ratio (AGR) and prognostic nutritional index (PNI) were calculated. Multivariable logistic analysis was used to identify predictors of high surgical difficulty. A predictive nomogram was developed and validated internally.

RESULTS

Among 294 patients included, 36 (12.4%) patients were graded as high surgical difficulty. Logistic regression analysis demonstrated that previous abdominal surgery (OR = 6.080, P = 0.001), tumor diameter (OR = 1.732, P = 0.003), intersphincteric resection (vs. low anterior resection, OR = 13.241, P < 0.001), interspinous distance (OR = 0.505, P = 0.009), and preoperative AGR (OR = 0.041, P = 0.024) were independently predictive of high surgical difficulty of LaTME after PCRT. Then, a predictive nomogram was built (C-index = 0.867).

CONCLUSION

Besides previous abdominal surgery, type of surgery (intersphincteric resection), tumor diameter, and interspinous distance, we found that preoperative AGR could be useful for the prediction of surgical difficulty of LaTME after PCRT. A predictive nomogram for surgical difficulty may aid in planning an appropriate approach for rectal cancer surgery after PCRT.

[Construction of artificial neural network model for predicting the efficacy of first-line FOLFOX chemotherapy for metastatic colorectal cancer]

Objective: To explore and establish an artificial neural network (ANN) model for predicting the efficacy of first-line FOLFOX chemotherapy for metastatic colorectal cancer. Methods: A set of FOLFOX chemotherapy data from a group of patients with metastatic colorectal cancer (mCRC) (GSE104645) was downloaded from the GEO database as a training set. According to the FOLFOX protocol, the efficacy was divided into two groups: the chemo-sensitive group (including complete response and partial response) and the chemo-resistant group (including stable disease and progressive disease), including 31 cases in the sensitive group and 23 in the resistant group. Then, chip data (accessible number: GSE69657) from Fujian Medical University Union Hospital were chosen as a test set. A total of 30 patients were enrolled in the study, including 13 in the sensitive group and 17 in the resistant group. The batch effect correction was performed on the expression values of the two sets of matrices using the R 3.5.1 software Combat package. The gene expression difference of sensitive and resistant group in GSE104645 was analyzed by the GEO2R platform. P<0.05 and the absolute value of log(2)FC>0.33 (FC abbreviation of fold change) were used as the threshold value to screen the drug resistance and sensitive genes of the FOLFOX regimen. An ANN was constructed using the multi-layer perceptron (MLP) to perform the FOLFOX regimen on the GSE104645 dataset. The GSE69657 expression matrix and clinical efficacy parameters were then used for retrospective verification. Receiver operating characteristic(ROC) curves were used to evaluate the test results and predictive power. Results: A total of 2, 076 differentially expressed genes in GSE104645 were selected, of which 822 genes were up-regulated and 1, 254 genes were down-regulated in the chemo-resistance group. The down-regulated genes were sensitive genes. GO analysis of the biological processes in which the differentially expressed genes were involved, revealed that they were mainly involved in the regulation of substance metabolism. A total of 39 genes were included in the final model construction. This was a neural network model with two hidden layers. The accuracy of predicting training samples and test samples was 75.7% and 76.5%, respectively, and the area under the ROC curve was 0.875. The chip data set of our department (GSE69657) was set as the test set, and the area under the ROC curve was 0.778. Conclusions: In this study, an artificial neural network model is successfully constructed to predict the efficacy of first-line FOLFOX regimen for metastatic colorectal cancer based on the microarray, and an independent external verification is also conducted. The model has good stability and well prediction efficiency. Besides, the results of this study suggest that the gene functions related to oxaliplatin resistance are mainly enriched in the regulation process of substance metabolism.

Short-term outcomes of complete mesocolic excision versus D2 dissection in patients undergoing laparoscopic colectomy for right colon cancer (RELARC): a randomised, controlled, phase 3, superiority trial

BACKGROUND

Whether extended lymphadenectomy for right colon cancer leads to increased perioperative complications or improves survival is still controversial. This trial aimed to compare the efficacy and safety of complete mesocolic excision (CME) versus D2 dissection in laparoscopic right hemicolectomy for patients with right colon cancer. This article reports the early safety results from the trial.

METHODS

This randomised, controlled, phase 3, superiority, trial was done at 17 hospitals in nine provinces of China. Eligible patients were aged 18-75 years with histologically confirmed primary adenocarcinoma located between the caecum and the right third of the transverse colon, without evidence of distant metastases. Central randomisation was done by means of the Clinical Information Management-Central Randomisation System via block randomisation (block size of four). Patients were randomly assigned (1:1) to CME or D2 dissection during laparoscopic right colectomy. Central lymph nodes were dissected in the CME but not in the D2 procedure. Neither investigators nor patients were masked to their group assignment but the quality control committee were masked to group assignment. The primary endpoint was 3-year disease-free survival, but the data for this endpoint are not yet mature; thus, only the secondary outcomes-intraoperative surgical complications and postoperative complications within 30 days of surgery, graded according to the Clavien-Dindo classification, mortality (death from any cause within 30 days of surgery), and central lymph node metastasis rate in the CME group only-are reported in this Article. This early analysis of safety was preplanned. The outcomes were analysed according to a modified intention-to-treat principle (excluding patients who no longer met inclusion criteria after surgery or who did not have surgery). This study is registered with ClinicalTrials.gov, NCT02619942. Study recruitment is complete, and follow-up is ongoing.

FINDINGS

Between Jan 11, 2016, and Dec 26, 2019, 1072 patients were enrolled and randomly assigned. After exclusion of 77 patients, 995 patients were included in the modified intention-to-treat population (495 in the CME group and 500 in the D2 dissection group). The postoperative surgical complication rate was 20% (97 of 495 patients) in the CME group versus 22% (109 of 500 patients) in the D2 group (difference, -2·2% [95% CI -7·2 to 2·8]; p=0·39); the frequency of Clavien-Dindo grade I-II complications were similar between groups (91 [18%] vs 92 [18%], difference, -0·0% [95% CI -4·8 to 4·8]; p=1·0) but Clavien-Dindo grade III-IV complications were significantly less frequent in the CME group than in the D2 group (six [1%] vs 17 [3%], -2·2% [-4·1 to -0·3]; p=0·022); no deaths occurred in either group. Of the intraoperative complications, vascular injury was significantly more common in the CME group than in the D2 group (15 [3%] vs six [1%], difference, 1·8 [95% CI 0·04 to 3·6]; p=0·045). Metastases in the central lymph nodes were detected in 13 (3%) of 394 patients who underwent central lymph node biopsy in the CME group; no patient had isolated metastases to central lymph nodes.

INTERPRETATION

Although the CME procedure might increase the risk of intraoperative vascular injury, it generally seems to be safe and feasible for experienced surgeons.

FUNDING

The Capital Characteristic Clinical Project of Beijing and the Chinese Academy of Medical Sciences.

Subtotal colectomy, extended right hemicolectomy, left hemicolectomy, or splenic flexure colectomy for splenic flexure tumors: a network meta-analysis

AIM

To perform a network meta-analysis of the current literature to evaluate the short-term and long-term outcomes of four operations for splenic flexure tumors.

METHODS

An electronic literature search of PubMed, Baidu Scholar, EMBASE, and Cochrane Central Register of Controlled Trials databases was performed up to August 2020. A Bayesian network meta-analysis was utilized to compare the outcomes involved in subtotal colectomy (STC), extended right hemicolectomy (ERHC), standard left hemicolectomy (LHC), and splenic flexure colectomy (SFC) by using R software.

RESULTS

A total of 10 non-randomized studies were included in this meta-analysis. There was no statistically significant difference among these 4 surgical techniques in terms of the utilization rate of minimally invasive surgery, reoperative surgery, anastomotic dehiscence, mortality, the proportion of patients with the number of lymph nodes harvested ≥ 12, local recurrence, distant recurrence and overall survival. Although ERHC was associated with a higher risk of postoperative ileus (ERHC vs SFC, OR = 6.4, 95% CI 1.4-45.0, P = 0.019), it has an advantage of a higher rate of primary anastomosis (ERHC vs LHC, OR = 4.2, 95% CI 1.3-18.0, P = 0.019) and a non-significant trend for lower anastomotic dehiscence when compared with more restrict resections.

CONCLUSION

SFC, LHC, ERHC and STC for the curative resection of splenic flexure tumors provide similar survival. An individualized surgical plan considering both long-term and short-term outcomes is necessary to select the appropriate operations.

Identification of LncRNAs Associated With FOLFOX Chemoresistance in mCRC and Construction of a Predictive Model

Oxaliplatin, fluorouracil plus leucovorin (FOLFOX) regimen is the first-line chemotherapy of patients with metastatic colorectal cancer (mCRC). However, studies are limited regarding long non-coding RNAs (lncRNAs) associated with FOLFOX chemotherapy response and prognosis. This study aimed to identify lncRNAs associated with FOLFOX chemotherapy response and prognosis in mCRC patients and to construct a predictive model. We analyzed lncRNA expression in 11 mCRC patients treated with FOLFOX chemotherapy before surgery (four sensitive, seven resistant) by Gene Array Chip. The top eight lncRNAs (AC007193.8, CTD-2008N3.1, FLJ36777, RP11-509J21.4, RP3-508I15.20, LOC100130950, RP5-1042K10.13, and LINC00476) for chemotherapy response were identified according to weighted correlation network analysis (WGCNA). A competitive endogenous RNA (ceRNA) network was then constructed. The crucial functions of the eight lncRNAs enriched in chemotherapy resistance were mitogen-activated protein kinase (MAPK) and proteoglycans signaling pathway. Receiver operating characteristic (ROC) analysis demonstrated that the eight lncRNAs were potent predictors for chemotherapy resistance of mCRC patients. To further identify a signature model lncRNA chemotherapy response and prognosis, the validation set consisted of 196 CRC patients from our center was used to validate lncRNAs expression and prognosis by quantitative PCR (qPCR). The expression of the eight lncRNAs expression between CRC cancerous and adjacent non-cancerous tissues was also verified in the validation data set to determine the prognostic value. A generalized linear model was established to predict the probability of chemotherapy resistance and survival. Our findings showed that the eight-lncRNA signature may be a novel biomarker for the prediction of FOLFOX chemotherapy response and prognosis of mCRC patients.

Combination of Preoperative Plasma Fibrinogen and Neutrophil-to-Lymphocyte Ratio (the F-NLR Score) as a Prognostic Marker of Locally Advanced Rectal Cancer Following Preoperative Chemoradiotherapy

BACKGROUND

Coagulation and inflammation play important roles in tumor progression. This study aimed to explore the prognostic impact of combined analysis of fibrinogen and neutrophil-to-lymphocyte (NLR) ratio (F-NLR score) in locally advanced rectal cancer (LARC) receiving preoperative chemoradiotherapy (pCRT) and radical surgery.

METHOD

Totally 317 patients were included. X-tile analysis was used to determine the optimal cutoff values of preoperative fibrinogen and NLR. F-NLR scores were defined as 2 (both high fibrinogen and NLR), 1 (one of these abnormalities), or 0 (neither abnormality). Time-dependent ROC analysis was used to evaluate the predictive accuracy of fibrinogen, NLR, and F-NLR score. Cox regression analysis was performed to evaluate the prognostic impact of the F-NLR score. A predictive nomogram for disease-free survival (DFS) was developed and validated internally.

RESULTS

One hundred and seventeen (36.9%), 156 (49.2%), and 44 (13.9%) patients had F-NLR score of 0, 1, and 2, respectively. Higher F-NLR score was associated with poorly differentiated tumors, deeper tumor invasion, lymph node metastasis, and more advanced pTNM stage (all P < 0.05). The 5-year OS rates in the F-NLR 0, 1, and 2 groups were 93.6%, 87.3%, and 68.4%, respectively (P < 0.001), while the 5-year DFS rates were 91.8%, 76.8%, and 56.1%, respectively (P < 0.001). Cox regression analysis demonstrated that F-NLR score (F-NLR 1, HR = 2.021, P = 0.046; F-NLR 2, HR = 3.356, P = 0.002), pTNM stage III (HR = 3.109, P = 0.009), and circumferential resection margin (CRM) involvement (HR = 3.120, P = 0.021) were independently associated with DFS. A nomogram for DFS was developed (C-index 0.708).

CONCLUSION

F-NLR score is a promising predictor for disease recurrence in LARC patients after pCRT.

MRI pelvimetry-based evaluation of surgical difficulty in laparoscopic total mesorectal excision after neoadjuvant chemoradiation for male rectal cancer

Purpose

Laparoscopic total mesorectal excision (LaTME) is technically demanding in rectal cancer after neoadjuvant chemoradiotherapy (NCRT). This study aimed to predict the surgical difficulty of LaTME after NCRT based on pelvimetric parameters.

Methods

This study enrolled 147 patients who underwent LaTME after NCRT. The surgical difficulty was graded as high or low according to the operative time, estimated blood loss, conversion to open surgery, postoperative hospital stay, and postoperative complications. Pelvimetry parameters were collected based on preoperative MRI. A logistic regression analysis was performed to identify predictors of high surgical difficulty, and a nomogram was developed.

Results

Totally, 18 (12.2%) patients were graded as high surgical difficulty. High surgical difficulty was correlated with a shorter interspinous distance (P = 0.014), a small angle α and γ (P = 0.008, P = 0.008, respectively), and a larger mesorectal area and mesorectal fat area (P = 0.041, P = 0.046, respectively). Tumor distance from the anal verge (OR = 0.619, P = 0.024), tumor diameter (OR = 3.747, P = 0.004), interspinous distance (OR = 0.127, P = 0.007), and angle α (OR = 0.821, P = 0.039) were independent predictors of high surgical difficulty. A predictive nomogram was developed with a C-index of 0.867.

Conclusion

A shorter tumor distance from the anal verge, larger tumor diameter, shorter interspinous distance, and smaller angle α could help to predict high surgical difficulty of LaTME in male LARC patients after NCRT.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00595-020-02211-3.

USP43 directly regulates ZEB1 protein, mediating proliferation and metastasis of colorectal cancer

Colorectal cancer is one of the most common malignant tumors of the digestive tract. In this study, we had examined the biological role of USP43 in colorectal cancer. USP43 protein and mRNA abundance in clinical tissues and five cell lines were analyzed with quantitative real-time PCR test (qRT-PCR) and western blot. USP43 overexpression treated DLD1 cells and USP43 knockdown treated SW480 cells were used to study cell proliferation, migration, colony formation, invasion, and the expression of epithelial-mesenchymal transformation (EMT) biomarkers. Moreover, ubiquitination related ZEB1 degradation was studied with qRT-PCR and western blot. The relationships between USP43 and ZEB1 were investigated with western blot, co-immunoprecipitation, migration, and invasion. USP43 was highly expressed in colorectal cancer tissues. USP43 overexpression and knockdown treatments could affect cell proliferation, colony formation, migration, invasion, and the expression of EMT associated biomarkers. Moreover, USP43 can regulate ZEB1 degradation through ubiquitination pathway. USP43 could promote the proliferation, migration, and invasion of colorectal cancer. Meanwhile, USP43 can deubiquitinate and stabilize the ZEB1 protein, which plays an important role in the function of colorectal cancer.

Reactivation of oncogenes involved in G1/S transcription and apoptosis pathways by low dose decitabine promotes HT29 human colon cancer cell growth in vitro

BACKGROUND

To examine the effects of low-dose decitabine (DAC) on the proliferation of HT-29 cell lines, and to explore the central mechanism by which low-dose DAC affects HT-29 cell proliferation using a systematic biological approach.

METHODS

First, we examined the global effects of DAC on cell proliferation, the cell cycle, and apoptosis in HT29 colon cancer cells. Then, a series test of cluster (STC) analysis and weighted gene coexpression network analysis (WGCNA) were employed to identify critical pathways involved in the response to DAC treatment using 3 datasets from the GEO database. Finally, the expression changes and promoter methylation levels of hub genes were further confirmed by in vitro experiments.

RESULTS

Low-dose DAC (less than 1 µM) promoted the proliferation and colony formation ability of HT-29 cell lines. The results of the system-level analysis, including STC analysis, WGCNA, and Gene set variation analysis (GSVA), showed that DAC modulated 3 critical pathways: G1/S-specific transcription involved in E2F-mediated regulation of Cyclin E-associated events, apoptosis pathways, and EMT pathways. Subsequent in vitro experiments showed that low-dose DAC (0.1 µM) promoted G1/S-specific transcription and decreased apoptosis rates. Then, several regulatory hub oncogenes in these 3 pathways, CCNE1, E2F1, BCL2, PCNA, FOXC1, VIM, CXCL1, and VCAM1, were further confirmed to be activated by DAC at either the mRNA or protein level. We chose the oncogene BCL2 as an example and detected its methylation status and the effect of low-dose DAC on BCL2 expression. Data from TCGA and Oncomine databases demonstrated that BCL2 was decreased in colon cancer compared with normal mucosa. Further analysis showed that BCL2 had an increased degree of promoter methylation in 12 methylated sites in colon cancer compared with normal colon tissues. Bisulfite sequencing PCR showed that low-dose DAC decreased the methylation rate at the BCL2 promoter region.

CONCLUSIONS

We concluded that low-dose DAC treatment resulted in a cancer-promoting effect in HT29 cell lines. Mechanistically, high methylation levels at the promoter region of oncogenes with dominant effects in CRC, such as BCL2 in HT29, might play a role in suppressing CRC by inhibiting oncogene expression. Low-dose DAC treatment triggered BCL2 expression by decreasing its promoter methylation level, thereby resulting in cancer promotion.

Predictive value of changes in the level of carbohydrate antigen 19-9 in patients with locally advanced rectal cancer treated with neoadjuvant chemoradiotherapy

AIM

The aim of this work was to explore the predictive value of changes in the level of carbohydrate antigen 19-9 (CA19-9) after neoadjuvant chemoradiotherapy (nCRT) and after surgery in patients with locally advanced rectal cancer (LARC).

METHOD

Patients with LARC who underwent nCRT and radical surgery (between 2011 and 2016) were divided into three groups according to pre-nCRT and post-nCRT CA19-9 levels as follows: normal pre-nCRT CA19-9 (normal CA19-9 group), elevated pre-nCRT and normal post-nCRT CA19-9 (normalized group) and elevated pre-nCRT and elevated post-nCRT CA19-9 (nonnormalized group). The pathological nCRT response criteria included ypCR and downstaging (ypStages 0-I). Recurrence-free survival (RFS) and overall survival (OS) were analysed.

RESULTS

A total of 721 patients were identified. The normal CA19-9 group was significantly associated with ypCR (n = 159) and downstaging (n = 347) (P < 0.05). The normalized group (n = 76) had worse RFS and OS than the normal CA19-9 group (n = 622) and better RFS and OS than the nonnormalized group (n = 23) (5-year RFS 47.0% vs 66.9% vs 81.5%, P < 0.001; 5-year OS 47.0% vs 75.4% vs 85.0%, P < 0.001). In multivariate analysis, CA19-9 group and ypTNM stage were independent predictors of RFS and OS. Moreover, for the 23 patients with elevated post-nCRT CA19-9 levels, the RFS and OS of patients with normalized postoperative CA19-9 levels were significantly better than those of patients with elevated postoperative CA19-9 levels (P < 0.05).

CONCLUSION

Following nCRT, changes in the CA19-9 level are a strong prognostic marker for long-term survival, and they may be helpful in the selection of patients who prefer more conservative surgery after chemoradiotherapy.

Robotic colorectal cancer surgery in China: a nationwide retrospective observational study

BACKGROUND

Robotic colorectal cancer surgery is widely accepted and applied. However, there is still no objective and comprehensive assessment on the data of nationwide multicenter series.

METHOD

A total of 28 medical centers in Mainland China participated in this nationwide retrospective observational study. From the first case performed in each center to the last until December 2017, patients with robotic resection for primary tumor and pathologically confirmed colorectal adenocarcinoma were consecutively enrolled. Clinical, pathological and follow-up data were collected and analyzed.

RESULTS

A total of 5389 eligible patients were finally enrolled in this study, composing 72.2% of the total robotic colorectal surgery volume of Mainland China in the same period. For resections of one bowel segment of primary tumor, the postoperative mortality rate was 0.08% (4/5063 cases), and the postoperative complication rate (Clavien-Dindo grade II or higher) was 8.6% (434/5063 cases). For multiple resections, the postoperative mortality rate was 0.6% (2/326 cases), and the postoperative complication rate was 16.3% (53/326 cases). Out of 2956 patients receiving sphincter-preserving surgery in only primary resection, 130 (4.4%) patients had anastomotic leakage. Traditional low anterior resection (tumor at middle rectum) (OR 2.384, P < 0.001), traditional low anterior resection (tumor at low rectum) (OR 1.968, P = 0.017) and intersphincteric resection (OR 5.468, P = 0.006) were significant independent risk factors for anastomotic leakage. Female gender (OR 0.557, P = 0.005), age ≥ 60 years (OR 0.684, P = 0.040), and preventive stoma (OR 0.496, P = 0.043) were significant independent protective factors. Body mass index, preoperative chemotherapy/radiotherapy, tumor size, and TNM stage did not independently affect the occurrence of anastomotic leakage.

CONCLUSION

Robotic colorectal cancer surgery was safe and reliable and might have advantages in patients at high risk of anastomotic leakage.

Data on patterns of initial recurrence after curative surgery for rectal cancer with neoadjuvant therapy

This paper accompanies the paper titled "Defining and predicting early recurrence in patients with locally advanced rectal cancer treated with neoadjuvant chemoradiotherapy" presented by the same authors to the European Journal of Surgical Oncology [1]. The present article describes the relevant clinical data of patterns of initial recurrence after curative surgery for rectal cancer with neoadjuvant therapy. This data was collected from the hospital records, Chinese Population Registration and Health Insurance System.

Mesorectal fat area and mesorectal area affect the surgical difficulty of robotic-assisted mesorectal excision and intersphincteric resection respectively in different ways

AIM

Many studies have demonstrated predictors of the difficulty of laparoscopic anterior resection for rectal cancer. Few studies focus on the influence of pelvic dimensions on robotic-assisted mesorectal excision (ME) and intersphincteric resection (ISR). This study aimed to evaluate the influences of the mesorectal fat area (MFA) and mesorectal area on the difficulty of robotic sphincter-saving surgery.

METHODS

We included 156 patients with middle and low rectal cancer who underwent robotic sphincter-saving surgery. Clinical and anatomical factors, including the pelvic dimensions, were collected. Linear regression was performed for variables associated with surgical duration. We also performed subgroup analyses for robotic-assisted ME and ISR. Logistic regression was used to find variables associated with transanal dissection.

RESULTS

For patients with middle or low rectal cancer, the sacral length and tumour distance from the anal verge were independently associated with surgical duration. The pT stage, sacral length and the MFA were independent predictors for the surgical duration of robotic-assisted ME. By contrast, a small mesorectal area was independently related to a longer duration of robotic-assisted ISR. The pelvic outlet length was independently associated with the use of transanal dissection for ISR.

CONCLUSION

It is suggested that a large MFA could affect the difficulty of ME in robotic-assisted ME, while a small mesorectal area could increase the surgical difficulty of robotic-assisted ISR for low rectal cancer. Besides, the pelvic outlet length was associated with the use of transanal dissection. Further studies are needed to validate the results and draw more scientific conclusions.