MRI navigation surgery, including lateral pelvic lymph node dissection following chemoradiotherapy, improves local control and functional preservation of the middle to low rectal cancer.

PURPOSE: The purpose of this study is to examine the appropriateness of MRI navigation surgery following chemoradiotherapy (CRT), including lateral pelvic lymph node dissection (LLND) for middle to low rectal cancer. METHODS: Forty-three consecutive patients with cT2-4b rectal cancer within 10 cm from the anal verge who underwent laparoscopic radical surgery following CRT (45-50.4Gy + S1 80mg/m2) from January 2014 and February 2020 were analyzed. We decided on the operative procedure, including LLND, based on the restaging MRI. We examined the rates of 3-year postoperative local pelvic recurrence, permanent stoma, and recurrent risk factors (Group S). We also compared the results to that of the fourteen patients who enrolled in the previous phase II trial and underwent laparoscopic radical surgery following CRT (40Gy + S-1 (80mg/m2) or UFT (300 mg/m2)) for consecutive cT2-4b rectal cancer below the peritoneal reflection. The operative procedure was decided at the initial MRI diagnosis, and the LLND was not performed (Group P). RESULTS: We had no local pelvic recurrence in Group S, and the three-year local pelvic recurrence-free survival was significantly better in Group S than P (100 % in S 85.1 % in P, p < 0.05). The permanent stoma rate was not different between the Groups, irrespective of the significantly high rate of cCRM(+) in Group S. The Cox proportional hazards model for significant factors of recurrence on the univariate analysis revealed that ycM and ycEMVI scores were independently significant (p < 0.001). CONCLUSION: MRI navigation surgery, including LLND for rectal cancer following chemoradiotherapy, improves local control and functional preservation.

Precision Identification of Locally Advanced Rectal Cancer in Denoised CT Scans Using EfficientNet and Voting System Algorithms.

BACKGROUND AND OBJECTIVE: Local advanced rectal cancer (LARC) poses significant treatment challenges due to its location and high recurrence rates. Accurate early detection is vital for treatment planning. With magnetic resonance imaging (MRI) being resource-intensive, this study explores using artificial intelligence (AI) to interpret computed tomography (CT) scans as an alternative, providing a quicker, more accessible diagnostic tool for LARC. METHODS: In this retrospective study, CT images of 1070 T3-4 rectal cancer patients from 2010 to 2022 were analyzed. AI models, trained on 739 cases, were validated using two test sets of 134 and 197 cases. By utilizing techniques such as nonlocal mean filtering, dynamic histogram equalization, and the EfficientNetB0 algorithm, we identified images featuring characteristics of a positive circumferential resection margin (CRM) for the diagnosis of locally advanced rectal cancer (LARC). Importantly, this study employs an innovative approach by using both hard and soft voting systems in the second stage to ascertain the LARC status of cases, thus emphasizing the novelty of the soft voting system for improved case identification accuracy. The local recurrence rates and overall survival of the cases predicted by our model were assessed to underscore its clinical value. RESULTS: The AI model exhibited high accuracy in identifying CRM-positive images, achieving an area under the curve (AUC) of 0.89 in the first test set and 0.86 in the second. In a patient-based analysis, the model reached AUCs of 0.84 and 0.79 using a hard voting system. Employing a soft voting system, the model attained AUCs of 0.93 and 0.88, respectively. Notably, AI-identified LARC cases exhibited a significantly higher five-year local recurrence rate and displayed a trend towards increased mortality across various thresholds. Furthermore, the model's capability to predict adverse clinical outcomes was superior to those of traditional assessments. CONCLUSION: AI can precisely identify CRM-positive LARC cases from CT images, signaling an increased local recurrence and mortality rate. Our study presents a swifter and more reliable method for detecting LARC compared to traditional CT or MRI techniques.

A comparison of whole-mount and conventional sections for pathological mesorectal extension and circumferential resection margin assessment after total mesorectal excision.

INTRODUCTION: The objective of the study is to compare 2 techniques for histological handling of rectal cancer specimens, namely whole-mount in a large block vs conventional sampling using small blocks, for mesorectal pathological assessment of circumferential resection margin status and depth of tumor invasion into the mesorectal fat. METHODS: This is a prospective study including 27 total mesorectal excision specimens of rectal cancer from patients treated for primary rectal carcinoma between 2020 and 2022 in a specialized multidisciplinary Colorectal Unit. For each total mesorectal excision specimen, 2 contiguous representative tumoral slices were selected and comparatively analyzed with whole-mount and small blocks macroscopic dissection techniques, enabling comparison between them in the same surgical specimen. The agreement between the 2 techniques to assess the distance of the tumor from the circumferential resection margin as well as the depth of tumor invasion was evaluated with the Student's t-test for paired samples, Pearson's correlation coefficient, and the Bland-Altman method comparison analysis. RESULTS: Complete mesorectal excision was observed in 8% of cases. Circumferential resection margin involvement was observed in only one case (4 %). The whole-mount and small block techniques obtained similar results when we assessed the distance to the circumferential resection margin (t-test P = 0.8, r = 0.92) and the depth of mesorectal infiltration (t-test P = 0.6, r = 0.95). CONCLUSIONS: Both gross dissection techniques (whole-mount vs multiple small cassettes) are equivalent and reliable to assess the distance to circumferential resection margin and the depth of mesorectal infiltration in the mesorectal fat in rectal cancer staging.

Progress of MRI in predicting the circumferential resection margin of rectal cancer: A narrative review.

Rectal cancer (RC) is the third most frequently diagnosed cancer worldwide, and the status of its circumferential resection margin (CRM) is of paramount significance for treatment strategies and prognosis. CRM involvement is defined as tumor touching or within 1 mm from the outermost part of tumor or outer border of the mesorectal or lymph node deposits to the resection margin. The incidence of involved CRM varied from 5.4 % to 36 %, which may associate with an in consistent definition of CRM, the quality of surgeries, and the different examination modalities. Although T and N status are essential factors in determining whether a patient should receive neoadjuvant therapy before surgery, CRM status is a powerful predictor of local and distant recurrence as well as survival rate. This review explores the significance of CRM, the various assessment methods, and the role of magnetic resonance imaging (MRI) and artificial intelligence-based MRI in predicting CRM status. MRI showed potential advantage in predicting CRM status with a high sensitivity and specificity compared to computed tomography (CT). We also discuss MRI advancements in RC imaging, including conventional MRI with body coil, high-resolution MRI with phased-array coil, and endorectal MRI. Along with a discussion of artificial intelligence-based MRI techniques to predict the CRM status of RCs before and after treatments.

Development of a joint prediction model based on both the radiomics and clinical factors for preoperative prediction of circumferential resection margin in middle-low rectal cancer using T2WI images.

OBJECTIVES: A circumferential resection margin (CRM) is an independent risk factor for local recurrence, distant metastasis, and poor overall survival of rectal cancer. In this study, we developed and validated a radiomics prediction model to predict perioperative surgical margins in patients with middle and low rectal cancer following neoadjuvant treatment and for decisions about treatment plans for patients. METHODS: This study retrospectively analyzed 275 patients from center 1(training cohort) and 120 patients from center 2(verification cohort) with rectal cancer diagnosed at two centers from July 2020 to July 2022 who underwent neoadjuvant therapy and had their CRM status confirmed by preoperative high-resolution magnetic resonance imaging (MRI) scans. Radiomics signatures were extracted and screened from MRI images and a radiomics signature was built by the least absolute shrinkage and selection operator (LASSO) logistic regression model, which was combined with clinical signatures to construct a nomogram. The receiver operating characteristic (ROC) curve and area under the curve (AUC) value, sensitivity, specificity, positive predictive value, negative predictive value, and calibration curve were used to evaluate the predictive performance of the model. RESULTS: In our research, the combined model has the best performance. In the training group, the radiomics model based on high-spatial-resolution T2-weighted imaging (HR-T2WI), clinical model and combined model demonstrated an AUC of 0.819 (0.802-0.833), 0.843 (0.822-0.861), and 0.910 (0.880-0.940), respectively. In the validation group, they demonstrated an AUC of 0.745 (0.715-0.788), 0.827 (0.798-0.850), and 0.848 (0.779-0.917), respectively. The calibration curve confirmed the clinical applicability of the model. CONCLUSIONS: The individualized prediction model established by combining radiomics signatures and clinical signatures can efficiently and objectively predict perioperative margin invasion in patients with middle and low rectal cancer.

Pelvic Diameter is not Associated with Positive Circumferential Resection Margin in Rectal Cancer: Retrospective Analysis of 78 Cases

Abstract Objective To identify if there is an association between pelvic entry and pelvic outlet diameters with increased positive circumferential resection margin (CRM) in rectal cancer. Introduction Positive CRMin rectalcancerisa majorpredictor forlocal anddistant recurrence. Pelvic diameters may be related to the difficulty of dissection, as well as intrinsic tumor characteristics such as tumor size, location, distance from the anal margin, and T stage, which may compromise the integrity of the mesorectum and circumferential margin involvement. Methods A retrospective review of the patient's medical records who underwent surgical resection of rectal adenocarcinoma from January 2012 to June 2022 was performed. The patient's preoperative staging, operative characteristics, and histopathologic outcomes were gathered from the medical records. Preoperative MRI scanning was done in all patients. MRI pelvimetry was done by two observers. CRM involvement was recorded as stated in the pathology report. Pelvimetry variables were dichotomized according to their mean values for correlation analysis. The odds ratio (OR) was calculated from a binary logistics regression model to assess the relation between the positive CRM and the independent variables. Results A total of 78 patients were included in this study. A positive CRM was reported in 10 patients (12.8%). BMI >27.4 + 6.6 (p = 0.02), positive extramural vascular invasion (p = 0.027), positive CRM by MRI scanning (p = 0.004), and anal sphincter involvement (p = 0.03) were associated with positive CRM. Pelvimetry values were not associated with a positive CRM. Conclusion No association was found between the pelvic diameters measured by MRI pelvimetry with a positive CRM.

Circumferential resection margin positivity due to direct or indirect tumour involvement in rectal cancer - a call for better stratification.

BACKGROUND: A positive circumferential resection margin (CRM) after rectal cancer surgery, which can be the result of direct or indirect tumour involvement, has consistently been associated with increased local recurrence and poorer survival. However, little is known of the differential impact of the mode of tumour involvement on outcomes. METHODS: 1460 consecutive patients undergoing rectal cancer resection between 2003 and 2018 were retrospectively assessed. Histopathology reports for patients with a positive CRM were reviewed to determine cases of direct (R1-tumour) or indirect tumour involvement (R1-other). Disease-free survival (DFS) and overall survival (OS) were assessed by Kaplan-Meier analysis. The role of the mode of CRM positivity was examined by univariate and multivariate Cox proportional hazards models. RESULTS: Eighty-five patients had an R1 resection due to CRM involvement (5.8%). Of those, 69 were due to direct tumour involvement, while 16 were from indirect causes. Kaplan-Meier analysis revealed that R1-other was associated with increased OS (hazard ratio 0.40, log-rank P = 0.006) and DFS (P = 0.043). Multivariate regression confirmed that the mode of CRM positivity was an independent predictor of OS. More interestingly, the patterns of recurrence were different between the two groups, with R1-tumour leading to significantly more local recurrence (P = 0.04). CONCLUSIONS: Our data strongly suggests that direct tumour involvement of the CRM confers worse prognosis after rectal cancer surgery. Importantly, differences in the site and frequency of recurrences make a case for better stratification of patients with a positive CRM to guide treatment decisions.

Impact of robotic total mesorectal excision upon pathology metrics in overweight males with low rectal cancer: a pooled analysis of 836 cases.

The aim of this pooled analysis was to evaluate the impact of robotic total mesorectal excision (TME) on pathology metrics in Male Overweight patients with Low rectal cancer (MOL). This was a multicenter retrospective pooled analysis of data. Two groups were defined: MOL (Male, Overweight, Low rectal cancer) and non-MOL. Overweight was defined as BMI ≥ 25 kg/m2. Low rectal cancer was defined as cancer within 6 cm from the anal verge. The primary endpoints of this study were histopathological metrics, namely circumferential resection margin (CRM) (mm), CRM involvement rate (%), and the quality of TME. Circumferential resection margin (CRM) was involved if < 1 mm. 836 (106 MOL and 730 non-MOL) patients that underwent robotic TME by six surgeons over 3 years were compared. No significant differences in demographics and perioperative variables were found, except for operating time, distal margin, and number of lymph nodes harvested. CRM involvement rate did not significantly differ (7.5% vs. 5.5%, p = 0.395). Mean CRM was statistically significantly narrower in MOL patients (6.6 vs. 7.7 mm, p = 0.04). Quality of TME did not differ. Distance of tumor from the anal verge was the only independent predictor of CRM involvement. Robotic TME may provide optimal pathology metrics in overweight males with low rectal cancer. Although CRM was a few millimeters narrower in MOL, the values were within the range of uninvolved margins making the difference statistically significant, but not clinically. Being MOL was not a risk factor for involvement of circumferential resection margin.

Impact of consolidation chemotherapy in poor responders to neoadjuvant radiation therapy: magnetic resonance imaging-based clinical-radiological correlation in high-risk rectal cancers.

PURPOSE: The current study was conducted to examine the role of consolidation chemotherapy after neoadjuvant radiation therapy (NART) in decreasing the involvement of the mesorectal fascia (MRF) in high-risk locally advanced rectal cancers (LARCs). METHODS: In total, 46 patients who received consolidation chemotherapy after NART due to persistent MRF involvement were identified from a database. A team of 2 radiologists, blinded to the clinical data, studied sequential magnetic resonance imaging (MRI) scans to assess the tumor response and then predict a surgical plan. This prediction was then correlated with the actual procedure conducted as well as histopathological details to assess the impact of consolidation chemotherapy. RESULTS: The comparison of MRI-based parameters of sequential images showed significant downstaging of T2 signal intensity, tumor height, MRF involvement, diffusion restriction, and N category between sequential MRIs (P < 0.05). However, clinically relevant downstaging (standardized mean difference, > 0.3) was observed for only T2 signal intensity and diffusion restriction on diffusion-weighted imaging. No clinically relevant changes occurred in the remaining parameters; thus, no change was noted in the extent of surgery predicted by MRI. Weak agreement (Cohen κ coefficient, 0.375) and correlation (Spearman rank coefficient, 0.231) were found between MRI-predicted surgery and the actual procedure performed. The comparison of MRI-based and pathological tumor response grading also showed a poor correlation. CONCLUSION: Evidence is lacking regarding the use of consolidation chemotherapy in reducing MRF involvement in LARCs. The benefit of additional chemotherapy after NART in decreasing the extent of planned surgery by reducing margin involvement requires prospective research.

Transanal Total Mesorectal Excision for Rectal Cancer: Toward Standardization of the Surgical Technique.

Laparoscopic surgery is widely used for rectal cancer; however, this technique is challenging due to tapering of the mesorectum in the pelvis, and the forward angle of the distal rectum, which renders this part of the rectum less accessible from the abdominal cavity. Hence, concerns regarding its safety and curability have been raised, particularly for inadequate distal and circumferential resection margins. Recently, transanal total mesorectal excision (TaTME), which involves endoscopic total mesorectal excision (TME) retrogradely from the anal side, has attracted attention worldwide as a solution to these problems. TaTME is superior to the conventional laparoscopic approach for rectal cancer in terms of both oncological and functional preservations. However, a shallow learning curve caused by the unfamiliar anatomical view from the anal side can pose challenges. Therefore, an efficient educational system needs to be established. Randomized controlled trials comparing conventional laparoscopic TME with TaTME are ongoing to demonstrate the usefulness of TaTME. This article reviews changes in the surgical treatment of rectal cancer, with a focus on TaTME, and describes the indications, surgical techniques, and training curricula for TaTME.

Positive Circumferential Resection Margin in Rectal Cancer Is a Robust Predictor of Poor Long-term Prognosis With Clinicopathological Bias Between Groups Compensated by Propensity-score Matching Analysis.

BACKGROUND/AIM: Circumferential resection margin (CRM) is the most reliable predictor of local and distant recurrence in locally-advanced rectal cancer (LARC). The present study was conducted to compare the long-term outcomes between CRM (+) and (-) groups using propensity-score (PS) matching analysis to compensate for bias between groups. PATIENTS AND METHODS: Of 563 consecutive patients with Stage II/III rectal cancer who were treated surgically with curative-intent at Juntendo University Hospital between Jan 1989 and Mar 2018, 412 patients were enrolled retrospectively in the study. The patients were divided into a CRM (+) group (n=21; 5.1%) and a CRM (-) group (n=391; 94.9%). RESULTS: In the entire cohort, recurrence-free survival (RFS), local recurrence-free survival (LRFS), non-local recurrence-free survival (NLRFS), and cancer-specific survival (CSS) were significantly worse among patients in the CRM (+) group compared with those in the CRM (-) group. Univariate analysis demonstrated patients in the CRM (+) group had significantly larger primary tumors (p=0.02), more frequently had open surgery (p=0.009), had an abdominoperineal resection (APR) procedure (p=0.01) and a T4 primary tumor (p<0.0001). After PS matching analysis, in the propensity-matched cohort, RFS, LRFS, NLRFS and CSS were significantly worse among patients in the CRM (+) group compared with those in the CRM (-) group. CONCLUSION: PS matching analysis demonstrated that RFS, LRFS, NLRFS, and CSS were significantly worse among patients in the CRM (+) group compared with those in the CRM (-) group. The present results indicate that CRM (+) is a robust predictor of long-term outcome of LARC, independent of tumor size.

The percentage of mesorectal infiltration as a prognostic factor after curative surgery for pT3 rectal cancer.

AIM: The aim of this study is to evaluate the prognostic value of a novel variable - the percentage of mesorectal infiltration (PMI) - in pT3 rectal cancer. METHOD: A cohort of 241 patients with pT3 rectal adenocarcinoma, operated on between February 2002 and May 2019, was selected for the analysis. Data concerning patient, treatment and tumour characteristics were collected. The depth of mesorectal infiltration (DMI) and the distance between the deepest invasion and the circumferential resection margin (CRM) were measured. The PMI was calculated using a formula combining these parameters. RESULTS: Neoadjuvant therapy was administered in 33.2% of cases. A complete mesorectal excision was achieved in 74% of patients. The CRM was affected in 24 patients (9.9%). The 5-year actuarial local recurrence (LR), overall recurrence (OR) and overall survival (OS) rates were 7.5%, 22.9% and 72.4%, respectively. The PMI was significantly associated with worse oncological outcomes regarding LR (p = 0.009), OR (p = 0.001) and OS (p = 0.016) rates. A cut-off value of PMI >60% had the highest specificity (80%) for LR (p = 0.026), OR (p = 0.04) and OS (p = 0.07). CONCLUSION: The PMI has an adverse prognostic impact on the oncological results following surgery for pT3 rectal cancer. It allows prediction of the risk of both LR and distant recurrence with higher accuracy than the DMI or the distance to the CRM. A PMI >60% may be used as a cut off value while subclassifying pT3 rectal tumours. It may influence decision-making while establishing adjuvant treatment and the follow-up schedule.

Optimization of treatment strategies based on preoperative imaging features and local recurrence areas for locally advanced lower rectal cancer after lateral pelvic lymph node dissection.

Purpose: Local recurrence (LR) is the main cause of treatment failure in locally advanced lower rectal cancer (LALRC). This study evaluated the preoperative risk factors for LR in patients with LALRC to improve the therapeutic strategies. Patients and Methods: LALRC patients who underwent total mesorectal excision (TME) with lateral pelvic lymph node (LPN) dissection (LPND) from January 2012 to December 2019 were reviewed. The log-rank test was used to assess local recurrence-free survival (LRFS), and multivariate Cox regression was used to identify the prognostic risk factors for LRFS. Follow-up imaging data were used to classify LR according to the location. Results: Overall, 376 patients were enrolled, and 8.8% (n=33) of these patients developed LR after surgery. Multivariate analysis identified positive clinical circumferential resection margin (cCRM) as an independent prognostic factor for LRFS (HR: 4.94; 95% CI, 1.75-13.94; P=0.003). The most common sites for LR were the pelvic plexus and internal iliac area (PIA) (54.5%), followed by the central pelvic area (CPA) (39.4%) and obturator area (OA) (6.1%). Following a subgroup analysis, LR in the OA was not associated with positive cCRM. Patients treated with upfront surgery (n=35, 14.1%) had a lower cCRM positive rate when compared with patients treated with neoadjuvant chemoradiotherapy (nCRT) (n=12, 23.5%). However, the LR rate in the nCRT group was still lower (n=28, 36.4%) than that in the upfront surgery group (n=35, 14.%). Among patients with positive cCRM, the LR rate in patients with nCRT remained low (n=3, 10.7%). Conclusion: Positive cCRM is an independent risk factor for LR after TME plus LPND in LALRC patients. LPND is effective and adequate for local control within the OA regardless of cCRM status. However, for LALRC patients with positive cCRM, nCRT should be considered before LPND to further reduce LR in the PIA and CPA.

Extralevator Abdominoperineal Excision (ELAPE) is Not Superior to Abdominoperineal Excision (APE) in the Era of Neoadjuvant Treatment in Rectal Cancer.

Aim: To evaluate the effect of extralevator abdominoperineal excision of the rectum (ELAPE) on the circumferential resection margin (CRM) and overall survival in comparison to standard abdominoperineal excision of the rectum (APE) in patients with advanced rectal cancer. Material and Methods: This retrospective study encompasses patients with advanced rectal cancer operated on with two different methods: prone Jack-Knife position ELAPE and APE. In part of them, neoadjuvant chemoradiation was conducted. Postoperative patient, tumor, and outcome data were analyzed in terms of differences in CRM positivity and overall survival. Results: Of 67 patients treated with either APE (52) or ELAPE (15), 43 were male and 24 were female. Neoadjuvant treatment was conducted on 49 of the total patients. Complete pathological response (T0) was achieved in 3 patients. Positive CRM was reported in 7 patients (11.5 %), 3 in ELAPE and 4 in APE group (p = 0.348). The overall postoperative complication rate was 56.7%. Mean survival period was 42.2 months. Overall survival rate for both groups was 67.2 %. No statistical differences were seen between the ELAPE and APE procedure in terms of overall survival (p = 0.483). Conclusions: Differences between the use of ELAPE and APE in terms of CRM positivity and overall survival were not statistically significant. Therefore, we conclude that ELAPE is not superior to standard APE in the treatment of advanced rectal cancer.

[Relationship of diffusion kurtosis imaging parameters with the pathologic type and prognosis of rectal tumors].

Objective: To explore the application value of diffusion kurtosis imaging (DKI) in the differential diagnosis of rectal tumors and evaluating the prognostic factors associated with rectal adenocarcinoma. Methods: A total of 105 patients with rectal tumors admitted in the First Affiliated Hospital of Zhengzhou University from December 2018 to August 2020 were retrospectively analyzed. All patients underwent high-resolution magnetic resonance DKI scanning. The mean diffusivity (MD), mean kurtosis (MK) and apparent diffusion coefficient (ADC) were measured and the relationship of these parameters with pathological types and prognostic factors of rectal tumor were analyzed. The diagnostic efficacy of MD, MK, and ADC for positive circumferential resection margin (CRM) and extramural venous invasion (EMVI) of rectal adenocarcinoma was evaluated by the receiver operating characteristic (ROC) curve. Results: MD and ADC were only related to pathological type. The MD and ADC were (2.091±0.390)×10(-3) and (1.478±0.265)×10(-3) mm(2)/s in mucinous adenocarcinoma, higher than (1.136±0.182)×10(-3) and (0.767±0.077)×10(-3) mm(2)/s in unspecified adenocarcinoma and (1.617±0.697)×10(-3) and (0.940±0.179)×10(-3) mm(2)/s in tubulo-villous adenoma. The MD and ADC in unspecified adenocarcinoma were lower than those in tubule-villous adenoma (P<0.05). Nevertheless, MK was associated with pathological type, N stage, CRM and EMVI. The MK was 0.566±0.110 in mucinous adenocarcinoma, lower than 0.982±0.135 in unspecified adenocarcinoma and 0.827±0.121 in tubulo-villous adenoma. The MK in unspecified adenocarcinoma was higher than that in intubulo-villous adenoma. The MK was 0.984±0.107 in pN1-2, higher than 0.881±0.146 in pN0. The MK was 0.990±0.142 in positive CRM, higher than 0.862±0.114 in negative CRM. The MK was 0.996±0.140 in positive EMVI, higher than 0.832±0.100 in negative EMVI (P<0.05). The ROC curves showed that the AUCs of MD, MK and ADC in diagnosing positive CRM were 0.459, 0.653 and 0.408, respectively; with MK=1.006 as the optimal diagnostic threshold, the diagnostic sensitivity and specificity were 51.9% and 81.0%, respectively. The AUCs of MD, MK and ADC values in diagnosing positive EMVI were 0.510, 0.662 and 0.388, respectively; with MK=1.010 as the optimal diagnostic threshold, the diagnostic sensitivity and specificity were 50.9% and 87.5%, respectively. Conclusions: DKI quantitative parameter is helpful for discriminating rectal tubulo-villous adenoma, unspecified adenocarcinoma, and mucinous adenocarcinoma, and is helpful for predicting the prognosis of patients with rectal adenocarcinoma. High MK is associated with positive CRM and EMVI.

The prognostic significance of the circumferential resection margin in esophageal squamous cell carcinoma patients without neoadjuvant treatment.

BACKGROUND: Circumferential resection margin (CRM) is very important in esophageal cancer, but its diagnostic criteria has not been unified. The College of American Pathologists (CAP) and the Royal College of Pathologists (RCP) provide two different criteria. The aim of this study is to evaluate the long-term prognostic significance of CRM status with different CRM criteria in esophageal squamous cell carcinoma (ESCC). METHODS: Influence of CRM status according to the CAP and RCP criteria on long-term survival of 838 patients with resected pT3 tumors and without neoadjuvant therapy was analyzed. Patients stratified into three groups on the basis of tumor distance from the CRM (CRM > 1 mm, 0-1 mm, and 0 mm) were also analysed. RESULTS: Positive CRM was found in 59 (7%) patients according to the CAP criteria and 317 (37.8%) patients according to the RCP criteria. Univariate and multivariate survival analysis showed that CRM status, according to three different criteria, was independent prognostic factor. However, subgroup analysis showed that the prognostic value of CRM status was limited to certain metastatic lymph node load. In pN0 subgroup, patients with CRM > 1 mm had better prognosis than patients with CRM 0-1 mm. Patients with CRM 0 mm had worse outcome than patients with CRM > 0 mm in pN1-2 subgroup. But CRM status had no prognosis value in pN3 subgroup. CONCLUSIONS: The CRM status is an important prognostic factor in ESCC patients, but this effect was limited to patients without or with less lymph node metastasis (pN0-2). In clinical practice, we recommend the 1 mm-three-tier criteria as it provides more prognostic value than the traditional two-tier criteria.

Incidence, predictors and prognostic implications of positive circumferential resection margin in colon cancer: A retrospective study in a Chinese high-volume cancer center.

Positive circumferential resection margin (CRM) was associated with a higher recurrence rate and worse survival in rectal cancer. Predictors of CRM in rectal cancer have widely been investigated. Our study aims to determine the incidence, predictors and prognostic implications of positive CRM following colon cancer (CC) surgery in a Chinese high-volume cancer center. The clinicopathological features and oncological outcomes of CC patients undergoing surgery between January 2008 and December 2018 were identified from Fudan University Shanghai Cancer Center database. Positive CRM was defined as resection margin ≤1 mm. A total of 5268 stage I-IV CC patients were identified in our study, 108 (2.05%) of whom had positive CRM. Multivariate logistic analysis found that advanced N stage, distant metastases and poorly differentiated tumor had increased risk of positive CRM. After propensity score matching, the 5-year overall survival rates of the patients with positive and negative CRM were 33.2% and 39.8% (P=0.005), respectively. Multivariable COX regression model showed that positive CRM was an independent prognostic factor for OS in CC patients. The overall rate of positive CRM in our center is lower than that in western population. Several adverse pathological parameters deserve more attention to identify CC patients at a high risk of positive CRM. Adoption of appropriate surgical techniques and multidisciplinary treatment planning are expected to improve oncological outcomes for high selected CC patients with "high-risk" CRM involvement.

Clinical Robotic Surgery Association (India Chapter) and Indian rectal cancer expert group's practical consensus statements for surgical management of localized and locally advanced rectal cancer.

Introduction: There are standard treatment guidelines for the surgical management of rectal cancer, that are advocated by recognized physician societies. But, owing to disparities in access and affordability of various treatment options, there remains an unmet need for personalizing these international guidelines to Indian settings. Methods: Clinical Robotic Surgery Association (CRSA) set up the Indian rectal cancer expert group, with a pre-defined selection criterion and comprised of the leading surgical oncologists and gastrointestinal surgeons managing rectal cancer in India. Following the constitution of the expert Group, members identified three areas of focus and 12 clinical questions. A thorough review of the literature was performed, and the evidence was graded as per the levels of evidence by Oxford Centre for Evidence-Based Medicine. The consensus was built using the modified Delphi methodology of consensus development. A consensus statement was accepted only if ≥75% of the experts were in agreement. Results: Using the results of the review of the literature and experts' opinions; the expert group members drafted and agreed on the final consensus statements, and these were classified as "strong or weak", based on the GRADE framework. Conclusion: The expert group adapted international guidelines for the surgical management of localized and locally advanced rectal cancer to Indian settings. It will be vital to disseminate these to the wider surgical oncologists and gastrointestinal surgeons' community in India.

Effect of circumferential resection margin status on survival and recurrence in esophageal squamous cell carcinoma with neoadjuvant chemoradiotherapy.

Background: The aim of this study was to investigate whether circumferential resection margin (CRM) status has an impact on survival and recurrence in esophageal squamous cell carcinoma after neoadjuvant chemoradiotherapy. Methods: We screened patients with esophageal squamous cell carcinoma who underwent esophagectomy from January 2017 to December 2019. The CRM was reassessed. Patients were grouped into a CRM of 1 mm or less (0 < CRM ≤ 1 mm) and a CRM greater than 1 mm (CRM>1 mm). The impact of CRM on survival was investigated using Kaplan-Meier analysis and Cox regression modeling. The optimal CRM cut point was evaluated using restricted cubic spline curve. Results: A total of 89 patients were enrolled in this study. The CRM status was an independent risk factor for the prognosis (HR: 0.35, 95% CI: 0.16-0.73). Compared with a CRM of 1 mm or less, a CRM greater than 1 mm had better overall survival (HR: 0.35, 95% CI: 0.16-0.73, log-rank P = 0.011), longer disease-free survival (HR: 0.51, 95% CI: 0.27-0.95, log-rank P = 0.040), and less recurrence (HR: 0.44, 95% CI: 0.23-0.85, log-rank P = 0.015). We visualized the association between CRM and the hazard ratio of survival and identified the optimal cut point at 1 mm. Conclusions: A CRM greater than 1 mm had better survival and less recurrence compared to a CRM of 1 mm or less. A more radical resection with adequate CRM could benefit survival in patients with esophageal squamous cell carcinoma after neoadjuvant therapy.

Minimum radial margin in pelvic exenteration for locally advanced or recurrent rectal cancer.

PURPOSE: The aim of this study was to clarify the suitable radial margin (RM) for favourable outcomes after pelvic exenteration (PE), focusing on the discrepancy between the concepts of circumferential resection margin (CRM) and traditional R status. METHODS: Seventy-three patients with locally advanced (LARC, n = 24) or locally recurrent rectal cancer (LRRC, n = 49) who underwent PE between 2006 and 2018 were retrospectively analysed. Patients were histologically classified into the following 3 groups; wide RM (≥1 mm, n = 45), narrow RM (0-1 mm, n = 10), and exposed RM (n = 18). The analysis was performed not only in the entire cohort but also in each disease group separately. RESULTS: The rates of traditional R0 (RM > 0 mm) and wide RM were 75.3% and 61.6%, respectively, resulting in the discrepancy rate of 13.7% between the two concepts. Preoperative radiotherapy was given in 12.3%. In the entire cohort, the local recurrence and overall survival (OS) rates for narrow RMs were significantly worse than those for wide RMs (p < 0.001 and p = 0.002), but were similar to those for exposed RMs. In both LARC and LRRC, RM < 1 mm resulted in significantly worse local recurrence and OS rates compared to the wide RMs. Multivariate analysis showed that RM < 1 mm was an independent risk factor for local recurrence in both LARC (HR 15.850, p = 0.015) and LRRC (HR 4.874, p = 0.005). CONCLUSIONS: Narrow and exposed RMs had an almost equal impact on local recurrence and poor OS after PE. Preoperative radiotherapy might have a key role to ensure a wide RM.