The "terminal line": a novel sign for the identification of distal mesorectum end during TME for rectal cancer.

Background: Although the clinical importance of complete, intact total mesorectal excision (TME) is the widely accepted standard for decreasing local recurrence of rectal cancer, the residual mesorectum still represents a significant component of resection margin involvement. This study aimed to use a visible intraoperative sign to detect the distal mesorectal end to ensure complete inclusion of the mesorectum and avoid unnecessary over-dissection. Methods: The distal mesorectum end was investigated retrospectively through a review of 124 operative videos at the Union Hospital of Fujian Medical University (Fujian, China) and Cleveland Clinic (Ohio, USA) by two independent surgeons who were blinded to each other. Furthermore, 28 cadavers and 44 post-operative specimens were prospectively examined by hematoxylin and eosin (H&E) staining and Masson's staining to validate and confirm the findings of the retrospective part. Univariate and multivariate analyses were carried out to detect the independent factors that can affect the visualization of the distal mesorectal end. Results: The terminal line (TL) is the distal mesorectal end of the transabdominal and transanal TME (taTME) and appears as a remarkable pearly white fascial structure extending posteriorly from 2 to 10 o'clock. Histopathological examination revealed that the fascia propria of the rectum merges with the presacral fascia at the TL, beyond which the mesorectum ends, with no further downward extension. In the retrospective observation, the TL was seen in 56.6% of transabdominal TME and 56.0% of taTME operations. Surgical approach and tumor distance from the anal verge were the independent variables that directly influenced the detection of the TL (P = 0.03 and P = 0.01). Conclusion: The TL is a visible sign where the transabdominal TME should end and the taTME should begin. Recognition of the mesorectal end may impact the certainty of complete mesorectum inclusion. Further clinical trials are needed to confirm the preliminary findings.

Deep Neural Network for the Prediction of KRAS Genotype in Rectal Cancer.

BACKGROUND: KRAS mutation can alter the treatment plan after resection of colorectal cancer. Despite its importance, the KRAS status of several patients remains unchecked because of the high cost and limited resources. This study developed a deep neural network (DNN) to predict the KRAS genotype using hematoxylin and eosin (H&E)-stained histopathological images. STUDY DESIGN: Three DNNs were created (KRAS_Mob, KRAS_Shuff, and KRAS_Ince) using the structural backbone of the MobileNet, ShuffleNet, and Inception networks, respectively. The Cancer Genome Atlas was screened to extract 49,684 image tiles that were used for deep learning and internal validation. An independent cohort of 43,032 image tiles was used for external validation. The performance was compared with humans, and a virtual cost-saving analysis was done. RESULTS: The KRAS_Mob network (area under the receiver operating curve [AUC] 0.8, 95% CI 0.71 to 0.89) was the best-performing model for predicting the KRAS genotype, followed by the KRAS_Shuff (AUC 0.73, 95% CI 0.62 to 0.84) and KRAS_Ince (AUC 0.71, 95% CI 0.6 to 0.82) networks. Combing the KRAS_Mob and KRAS_Shuff networks as a double prediction approach showed improved performance. KRAS_Mob network accuracy surpassed that of two independent pathologists (AUC 0.79 [95% CI 0.64 to 0.93], 0.51 [95% CI 0.34 to 0.69], and 0.51 (95% CI 0.34 to 0.69]; p < 0.001 for all comparisons). CONCLUSION: The DNN has the potential to predict the KRAS genotype directly from H&E-stained histopathological slide images. As an algorithmic screening method to prioritize patients for laboratory confirmation, such a model might possibly reduce the number of patients screened, resulting in significant test-related time and economic savings.

Outcome and quality of life in obese patients underwent laparoscopic vs. open appendectomy.

BACKGROUND: Although obesity is a popular reason for choosing laparoscopic appendectomy (LA) versus open appendectomy (OA), however, the question of whether there is a difference remains. Our goal is to investigate if there is a difference between OA and LA in obese patients. METHODS: Fifty-eight obese patients diagnosed with acute appendicitis according to ALVARDO score at department of surgery at Suez Canal university hospitals from March 2020 till August 2021 were included. The study participants were assigned in two groups LA and OA. This study aimed to comparing between LA and OA regarding intraoperative complications, length of hospital stays, post -operative pain, and rate of post-operative complications. Meanwhile, using SF-36 scoring questionnaire, the quality of life was compared between both groups. RESULTS: A total of 58 patients were included in the present study (LG = 29 patients and OG = 29 patients). The early post-operative complications (within 30 days after surgery) were significantly lower in the LA group (5 patients out of 29) than the OA (11 patients out of 29). Additionally, lower incidence of complications was noticed in the LA group (2 out of 29 patients) compared to OA (6 patients out of 29) beyond 30 days after operation. Patients with laparoscopic surgery had statistically significant higher overall quality of life scores (SF-36) (72 ± 32) compared to open surgery patients (66 ± 35) 2 weeks after operation. CONCLUSION: The laparoscopic procedure was associated with lower incidence of post operative complications. However, open appendectomy was superior for a shorter operative time. Laparoscopic approach is not only used for therapeutic purposes, but also it has a diagnostic role.

Role of the triad of procalcitonin, C-reactive protein, and white blood cell count in the prediction of anastomotic leak following colorectal resections.

PURPOSE: The enhanced recovery after surgery (ERAS) program expedites patient recovery after major surgery. This study aimed to investigate the role of the triad of procalcitonin (PCT), C-reactive protein (CRP), and white blood cells (WBC) trajectories as a predictive biomarker for the anastomotic leak (AL) after colorectal surgery. METHOD: Patients who had colorectal anastomosis were prospectively included. Postoperative clinical and laboratory parameters and outcomes were collected and analyzed. The 5-day trajectories of PCT, CRP, and WBC were evaluated. Based on the trajectory of the three biomarkers, we compared patients with and without AL as detected during the first 30 days after surgery using the area under receiver operator characteristic curves (AUC) for logistic estimation. RESULTS: This study included 205 patients, of whom 56% were men and 43.9% were women with a mean age of 56.4 ± 13.1 years. Twenty-two patients (10.7%) had AL; 77.3% underwent surgery, and 22.7% were treated with drainage and antibiotics. Procalcitonin was the best predictor for AL compared to CRP and WBC at three days postoperatively (AUC: 0.84, 0.76, 0.66, respectively). On day 5, a cutoff value of 4.93 ng/mL for PCT had the highest sensitivity, specificity, and negative predictive value. The predictive power of PCT was substantially improved when combined with either CRP or WBC, or both (AUC: 0.92, 0.92, 0.93, respectively). CONCLUSION: The 5-day trajectories of combined CRP, PCT, and WBC had a better predictive power for AL than the isolated daily measurements. Combining the three parameters may be a reliable predictor of early patient discharge, which would be highly beneficial to ERAS programs.

Anatomy of the perirectal fascia at the level of rectosacral fascia revisited.

BACKGROUND: The relative anatomical understanding of the perirectal fasciae is of paramount importance for the proper performance of total mesorectal excision (TME). This study was to demonstrate the planes of TME and validates the intraoperative findings using cadaveric observations. METHODS: In this combined retrospective and prospective study, bilateral attachment of the rectosacral fascia (RSF) was observed in 28 cadaveric specimens (male, n = 14; female, n = 14). From January 2018 to December 2019, surgical videos of 67 patients who underwent laparoscopic TME at the Affiliated Union Hospital of Fujian Medical University (Fuzhou, China) were reviewed and interpreted with the cadaveric findings. RESULTS: The RSF (synonym: Waldeyer's fascia) is the end of the pre-hypogastric fascia at the level of S4 and comprises two layers (upper and lower). These two layers provide double fascial protection for the venous sacral plexus. It inserts into the fascia propria of the rectum along a broad horizontal arc that merges anterolaterally in an oblique downward direction until it meets the posterolateral merge of Denonvilliers' fascia at the lateral rectal ligament (LRL). This ligament does not look like a true ligament but is more likely to be a fascial combination that cushions the rectal innervation and middle rectal vessels. CONCLUSIONS: Understanding the lateral attachment of RSF and its contribution to LRL provides invaluable surgical guidance to dissect this critical area. Therefore, lateral dissection is proposed from the anterior to the posterior direction to find the correct plane that guarantees an intact mesorectal envelope to protect the important nearby nerve structures.

Impact of Surgical Approach on Surgical Resection Quality in Mid- and Low Rectal Cancer, A Bayesian Network Meta-Analysis.

AIM: To evaluate the evidence concerning the quality of surgical resection in laparoscopic (LapTME), robotic (RobTME) and transanal (TaTME) total mesorectal excision for mid-/low rectal cancer. METHODS: A systematic literature search of the PubMed, EMBASE and Cochrane Central Register of Controlled Trials databases was performed. A Bayesian network meta-analysis was utilized to compare surgical resection involved in these 3 surgical techniques by using ADDIS software. Rates of positive circumferential resection margins (CRMs) were the primary endpoint. RESULTS: A total of 34 articles, 2 randomized clinical trials (RCTs) and 32 non-RCTs, were included in this meta-analysis. Pooled data showed CRM positivity in 114 of 1763 LapTME procedures (6.5%), 54 of 1051 RobTME procedures (5.1%) and 60 of 1276 TaTME procedures (4.7%). There was no statistically significant difference among these 3 surgical approaches in terms of CRM involvement rates and all other surgical resection quality outcomes. The incomplete mesorectal excision rates were 9.6% (69/720) in the LapTME group, 1.9% (11/584) in the RobTME group and 5.6% (45/797) in the TaTME group. Pooled network analysis observed a higher but not statistically significant risk of incomplete mesorectum when comparing both LapTME with RobTME (OR = 1.99; 95% CI = 0.48-11.17) and LapTME with TaTME (OR = 1.90; 95% CI = 0.99-5.25). By comparison, RobTME was most likely to be ranked the best or second best in terms of CRM involvement, complete mesorectal excision, rate of distal resection margin (DRM) involvement and length of DRMs. In addition, RobTME achieved a greater mean tumor distance to the CRM than TaTME. It is worth noting that TaTME was most likely to be ranked the worst in terms of CRM involvement for intersphincteric resection of low rectal cancer. CONCLUSION: Overall, RobTME was most likely to be ranked the best in terms of the quality of surgical resection for the treatment of mid-/low rectal cancer. TaTME should be performed with caution in the treatment of low rectal cancer.

A Comprehensive Repertoire of Transfer RNA-Derived Fragments and Their Regulatory Networks in Colorectal Cancer.

To provide systematic insight into the composition and expression of transfer RNA (tRNA) derivatives transcriptome in colorectal cancer (CRC). tRNA derivatives expression profiles in three pairs of CRC and adjacent normal colon tissues were performed by tRNA-derived small RNA fragments (tRFs) and tRNA halves (tiRNA) sequencing, and microarray data of transcriptomes from CRC and paired controls were retrieved from Gene Expression Omnibus database. The differentially expressed tRFs and tiRNAs and differentially expressed genes between CRC and paired normal samples were screened. The functional regulations between tRF and tiRNA and gene were identified. A total of 60 upregulated and 48 downregulated tRNA derivatives and 7373 upregulated and 12,138 downregulated messenger RNA (mRNA) were identified. The tRF and tiRNA-gene regulatory modules were constructed by analyzing computational tRF and tiRNA-target predictions and inverse expression relationships between tRF and tiRNAs and mRNA. Gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway annotation showed that the function of targets of tiRNA-Tyr-GTA was mainly enriched in negative regulation of epithelial cell apoptotic process and peroxisome proliferator activated-receptors (PPAR) signaling pathway. Cellular response to monoamine stimulus and inflammatory bowel disease was enriched in function of tiRNA-Val-CAC. Two functions, including negative regulation of c-Jun N-terminal kinase (JNK) cascade and choline metabolism in cancer, were enriched in tRF-Gln-CTG. The function of mesenchymal to epithelial transition was enriched in tRF-Leu-TAG. For the first time to our knowledge, our study provided a landscape of tRNA derivatives expression profiles in CRC. Further tRF and tiRNA-gene regulatory modules construction explored the potential functions related to these tRNA derivatives in the pathogenesis of CRC.

The impact of circumferential tumour location on the clinical outcome of rectal cancer patients managed with neoadjuvant chemoradiotherapy followed by total mesorectal excision.

AIM: To investigate the impact of circumferential tumour location on neoadjuvant chemoradiotherapy (CRT) response and its prognostic value for locally advanced rectal cancer (LARC) patients after CRT and surgery. METHODS: A retrospective study was performed on 486 patients with LARC who received neoadjuvant CRT and surgical treatment. The rate of pathological complete response (pCR) and survival among patients with anteriorly, laterally, and posteriorly located tumours were compared. Logistic regression was performed to identify pCR predictors. RESULTS: The anterior tumours exhibited the highest pCR rate of 26.7%, which was slightly higher than the 20.0% and 12.3% for lateral and posterior tumours, respectively (P = 0.006). The 5-year Overall survival (OS) rates after CRT were similar among the anterior, lateral, and posterior groups (anterior vs lateral vs posterior: 81.1% vs 89.9% vs 84.1%, P = 0.6368). Multivariate analysis revealed that the circumferential tumour location, post-CRT serum CEA and post-CRT tumour thickness measured by MRI were independently correlated with achieving pCR. CONCLUSION: This study is the first, to the best of our knowledge, to show that anterior LARC exhibited the highest pCR rate after neoadjuvant CRT. Patients with anterior rectal cancers do not have different prognoses from those with non-anterior cancers if they undergo neoadjuvant CRT.

Hypermethylated and downregulated MEIS2 are involved in stemness properties and oxaliplatin-based chemotherapy resistance of colorectal cancer.

The resistance against oxaliplatin (L-OHP) based regimens remains a major obstacle for its efficient usage in treating metastatic colorectal cancer (mCRC). In this study, we performed weighted gene coexpression network analysis (WGCNA) to systematically screen the relevant hub genes for L-OHP resistance using the raw microarray data of 30 consecutive mCRC samples from our earlier study (GSE69657). The results were further confirmed through datasets from Gene Expression Omnibus (GEO). From L-OHP resistance module, nine genes in both the coexpression and protein-protein interaction networks were chosen as hub genes. Among these genes, Meis Homeobox 2 (MEIS2) had the highest correlation with L-OHP resistance (r = -0.443) and was deregulated in L-OHP resistant tissues compared with L-OHP sensitive tissues in both our own dataset and GSE104645 testing dataset. The receiver operating characteristic curve validated that MEIS2 had a good ability in predicting L-OHP response in both our own dataset (area under the curve [AUC] = 0.802) and GSE104645 dataset (AUC = 0.746). Then, the down expression of MEIS2 was observed in CRC tissue compared with normal tissue in 12 GEO-sourced datasets and The Cancer Genome Atlas (TCGA) and was correlated with poor event-free survival. Furthermore, analyzing methylation data from TCGA showed that MEIS2 had increased promoter hypermethylation. In addition, MEIS2 expression was significantly decreased in CRC stem cells compared with nonstem cells in two GEO datasets (GSE14773 and GSE24747). Further methylation analysis from GSE104271 demonstrated that CRC stem cells had higher MEIS2 promoter methylation levels in cg00366722 and cg00610348 sites. Gene set enrichment analysis showed that MEIS2 might be involved in the Wnt/ß-catenin pathway. In the overall view, MEIS2 had increased promoter hypermethylation and was downregulated in poor L-OHP response mCRC tissues. MEIS2 might be involved in the Wnt/ß-catenin pathway to maintain CRC stemness, which leads to L-OHP resistance.

Downregulated SPINK4 is associated with poor survival in colorectal cancer.

BACKGROUND: SPINK4 is known as a gastrointestinal peptide in the gastrointestinal tract and is abundantly expressed in human goblet cells. The clinical significance of SPINK4 in colorectal cancer (CRC) is largely unknown. METHODS: We retrieved the expression data of 1168 CRC patients from 3 Gene Expression Omnibus (GEO) datasets (GSE24551, GSE39582, GSE32323) and The Cancer Genome Atlas (TCGA) to compare the expression level of SPINK4 between CRC tissues and normal colorectal tissues and to evaluate its value in predicting the survival of CRC patients. At the protein level, these results were further confirmed by data mining in the Human Protein Atlas and by immunohistochemical staining of samples from 81 CRC cases in our own center. RESULTS: SPINK4 expression was downregulated in CRC compared with that in normal tissues, and decreased SPINK4 expression at both the mRNA and protein levels was associated with poor prognosis in CRC patients from all 3 GEO datasets, the TCGA database and our cohort. Additionally, lower SPINK4 expression was significantly related to higher TNM stage. Moreover, in multivariate regression, SPINK4 was confirmed as an independent indicator of poor survival in CRC patients in all databases and in our own cohort. CONCLUSIONS: We concluded that reduced expression of SPINK4 relates to poor survival in CRC, functioning as a novel indicator.

Coexpression network analysis linked H2AFJ to chemoradiation resistance in colorectal cancer.

Neoadjuvant chemoradiotherapy (CRT) resistance is a complex phenomenon and it remains a major problem for patients with a priori resistant tumor. Therefore, there is a strong need to investigate molecular biomarkers which may guide for treatment decision-making. In our study, weighted gene coexpression network analysis was applied to identify CRT-resistance hub modules in 12 colorectal cancer (CRC) cell lines with different CRT sensitivities from GSE20298 data set. The green module and purple module had the highest correlations with CRT resistance. Gene ontology enrichment analysis indicated that the function of these two modules focused on interferon-mediated signaling pathway, immune response, chromatin modulation, Rho GTPases activities, and regulation of apoptotic process. Then, 15 hub genes in both the coexpression and protein-protein interaction networks were selected. Among these hub genes, higher H2A histone family member J (H2AFJ) expression was independently validated in patient cohorts from two testing data sets of GSE46862 and GSE68204 to be related to CRT resistance. The receiver operating characteristic curve showed that H2AFJ could efficiently distinguish CRT-resistance cases from CRT-sensitive cases in another two testing data sets. Furthermore, meta-analysis of 12 Gene Expression Omnibus-sourced data sets showed that H2AFJ messenger RNA levels were significantly higher in CRC tissues than in normal colon tissues. High H2AFJ expression was correlated with a significant worse event- and relapse-free survival by analyzing the data from the R2: Genomics Analysis and Visualization Platform. Gene set enrichment analysis determined that the mechanism of H2AFJ-mediated CRT resistance might involve the ERK5 (MAPK7), human immunodeficiency virus Nef (HIV Nef), and inflammatory pathways. This study is the first, to the best of our knowledge, to implicate and verify H2AFJ as an effective new marker for CRT response prediction.

Survival outcome of adjuvant radiotherapy after local excision for T2 early rectal cancer: An analysis based on the surveillance, epidemiology, and end result registry database.

BACKGROUND: Major resection (MR) is recommended for cases with T2 finding after local excision (LE) of early rectal cancer, but the revision procedure is accompanied with high morbidity. We evaluated the oncological safety of LE followed by adjuvant radiotherapy as a rectum-preserving alternative to MR for T2 early rectal cancer. METHODS: A total of 3786 patients with T2N0M0 rectal adenocarcinoma between 1998 and 2013 were included from the SEER database. Survival rates were compared using the Kaplan-Meier method with a log-rank test, and multivariate analyses were performed using Cox proportional regression models. RESULTS: Of these patients included, 429 (11.3%) treated with LE alone (LE group), 3067 (81.0%) treated with MR (MR group), and 290 (7.7%) treated with LE followed by adjuvant radiotherapy (LE + adjuvant RT group). The 5-year cancer specific survival (CSS) rate and 5-year overall survival (OS) rate were significantly lower in LE patients group than those in MR patients group (70.5% vs. 81.8%, P < 0.001; 57.3% vs. 72.3%, P < 0.001). The 5-year CSS rate and 5-year OS rate were similar between LE + adjuvant RT and MR groups (78.4% vs. 81.8%, P = 0.975, and 70.7% vs. 72.3%, P = 0.311, respectively). Multivariate Cox regression revealed that treatment strategies, age and CEA status were independently associated with CSS and OS. After age adjustment, LE was associated with reduced CSS (using MR as a reference, HR, 1.784; P < 0.001) and reduced OS (HR, 1.739; P < 0.001). However, CSS and OS related to LE + adjuvant RT of T2 rectal cancer group weren't be affected (HR, 0.994; P = 0.962 and HR, 0.904; P = 0.302, respectively). CONCLUSIONS: When MR is inappropriate for T2 early rectal cancer patients because of patients refusal or co-morbidities, LE + adjuvant RT can provide acceptable levels of long-term survival.