Resection Margin In Rectal Cancer Research Articles

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 CRM in rectal cancer is a major predictor for local and distant 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.

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.

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. 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%). 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. 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.

Predictors of Positive Circumferential Resection Margin in Rectal Cancer: A Current Audit of the National Cancer Database.

Positive circumferential resection margin is a predictor of local recurrence and worse survival in rectal cancer. National programs aimed to improve rectal cancer outcomes were first created in 2011 and continue to evolve. The impact on circumferential resection margin during this time frame has not been fully evaluated in the United States. The purpose of this study was to determine the incidence and predictors of positive circumferential resection margin after rectal cancer resection, across patient, provider, and tumor characteristics. This was a retrospective cohort study. The study was conducted using the National Cancer Database, 2011-2016. Adults who underwent proctectomy for pathologic stage I to III rectal adenocarcinoma were included. Rate and predictors of positive circumferential resection margin, defined as resection margin ≤1 mm, were measured. Of 52,620 cases, circumferential resection margin status was reported in 90% (n = 47,331) and positive in 18.4% (n = 8719). Unadjusted analysis showed that patients with positive circumferential resection margin were more often men, had public insurance and shorter travel, underwent total proctectomy via open and robotic approaches, and were treated in Southern and Western regions at integrated cancer networks (all p < 0.001). Multivariate analysis noted that positive proximal and/or distal margin on resected specimen had the strongest association with positive circumferential resection margin (OR = 15.6 (95% CI, 13.6-18.1); p < 0.001). Perineural invasion, total proctectomy, robotic approach, neoadjuvant chemoradiation, integrated cancer network, advanced tumor size and grade, and Black race had increased risk of positive circumferential resection margin (all p < 0.050). Laparoscopic approach, surgery in North, South, and Midwest regions, greater hospital volume and travel distance, lower T-stage, and higher income were associated with decreased risk (all p < 0.028). This was a retrospective cohort study with limited variables available for analysis. Despite creation of national initiatives, positive circumferential resection margin rate remains an alarming 18.4%. The persistently high rate with predictors of positive circumferential resection margin identified calls for additional education, targeted quality improvement assessments, and publicized auditing to improve rectal cancer care in the United States. See Video Abstract at http://links.lww.com/DCR/B584. ANTECEDENTES:El margen positivo de resección circunferencial es un predictor de recurrencia local y peor sobrevida en el cáncer de recto. Los programas nacionales destinados a mejorar los resultados del cáncer de recto se crearon por primera vez en 2011 y continúan evolucionando. La repercusión del margen de resección circunferencial durante este período de tiempo no se ha evaluado completamente en los Estados Unidos.OBJETIVO:Determinar la incidencia y los predictores para un margen positivo de resección circunferencial posterior a la resección del cáncer de recto, según las características del paciente, el proveedor y el tumor.DISEÑO:Estudio de cohorte retrospectivo.AMBITO:Base de datos nacional de cáncer, 2011-2016.PACIENTES:Adultos que se sometieron a proctectomía por adenocarcinoma de recto con un estadío por patología I-III.PRINCIPALES VARIABLES EVALUADAS:Tasa y predictores para un margen positivo de resección circunferencial, definido como margen de resección ≤ 1 mm.RESULTADOS:De 52,620 casos, la condición del margen de resección circunferencial se informó en el 90% (n = 47,331) y positivo en el 18.4% (n = 8,719). El análisis no ajustado mostró que los pacientes con margen positivo de resección circunferencial se presentó con mayor frecuencia en hombres, tenían un seguro social y viajes más cortos, se operaron de proctectomía total abierta y robótica, y fueron tratados en las regiones del sur y el oeste en redes integradas de cáncer (todos p <0,001). El análisis multivariado destacó que el margen proximal y / o distal positivo de la pieza resecada tenía la asociación más fuerte con el margen postivo de resección circunferencial (OR 15,6; IC del 95%: 13,6-18,1, p <0,001). La invasión perineural, la proctectomía total, el abordaje robótico, la quimioradioterapia neoadyuvante, la red de cáncer integrada, el tamaño y grado del tumor avanzado y la raza afroamericana tenían un mayor riesgo de un margen de una resección positiva circunferencial (todos p <0,050). El abordaje laparoscópico, la cirugía en las regiones Norte, Sur y Medio Oeste, un mayor volumen hospitalario y distancia de viaje, estadio T más bajo y mayores ingresos se asociaron con una disminución del riesgo (todos p <0,028).LIMITACIONES:Estudio de cohorte retrospectivo con variables limitadas disponibles para análisis.CONCLUSIONES:A pesar del establecimiento de iniciativas nacionales, la tasa de margen positivo de resección circunferencial continúa siendo alarmante, 18,4%. El índice continuamente elevado junto a los predictores de un margen positivo de resección circunferencial hace un llamado para una mayor educación, evaluaciones específicas de mejora de la calidad y difusión de las auditorías para mejorar la atención del cáncer de recto en los Estados Unidos. Vea el resumen de video en http://links.lww.com/DCR/B584. Consulte Video Resumen en http://links.lww.com/DCR/B584.

Management of the positive pathologic circumferential resection margin in rectal cancer: A national cancer database (NCDB) study

BackgroundThe circumferential resection margin (CRM) is a primary predictor of local recurrence and survival in rectal cancer, and an important consideration in guiding treatment. CRM is usually predicted preoperatively, so optimal management of an unexpected pathologic positive CRM involvement is debatable. We aimed to investigate the postoperative management of T3N0 rectal cancers with a positive pathologic CRM, and the impact of each strategy on survival. MethodsThe NCDB was reviewed for pathological T3N0 rectal cancer cases from 2010 to 2015, that received neoadjuvant chemotherapy, had surgical resection with pathological clear margins, but a positive pathologic CRM(disease≤2 mm from radial margin). The main outcomes were the incidence, treatment modalities used, and impact of each modality on survival. Univariate analysis evaluated the demographic and provider characteristics across treatment groups. Kaplan-Meier and Cox regression analysis assessed survival and factors associated with overall survival (OS). ResultsOf 1607 cases with a positive CRM, 65% (1045) received no adjuvant treatment and 35% (n = 562) received adjuvant chemotherapy (AC). After matching, the 1-, 3-, and 5-year OS rates were 98.5%, 88.6% and 76.6% for AC and 96.9%, 84.6% and 68.4% for with no treatment (p = .027). Factors independently associated with improved OS were treatment at an academic/research facility (p = .009), minimally invasive approach (p = .005), well and moderately differentiated tumor (p < .001), absence of perineural invasion (p = .015) and AC administration (p = .047). ConclusionIn T3N0 rectal cancers resected with local clear margins but a positive pathologic CRM, AC improved OS. However, only a third received this option. Further study is needed to investigate the disparities in AC use in these patients with unexpected pathologic results.

Application of convolutional neural network to risk evaluation of positive circumferential resection margin of rectal cancer by magnetic resonance imaging

Objective: To explore the feasibility of using faster regional convolutional neural network (Faster R-CNN) to evaluate the status of circumferential resection margin (CRM) of rectal cancer in the magnetic resonance imaging (MRI). Methods: This study was registered in the Chinese Clinical Trial Registry (ChiCTR-1800017410). Case inclusion criteria: (1) the positive area of CRM was located between the plane of the levator ani, anal canal and peritoneal reflection; (2) rectal malignancy was confirmed by electronic colonoscopy and histopathological examination; (3) positive CRM was confirmed by postoperative pathology or preoperative high-resolution MRI. Exclusion criteria: patients after neoadjuvant therapy, recurrent cancer after surgery, poor quality images, giant tumor with extensive necrosis and tissue degeneration, and rectal tissue construction changes in previous pelvic surgery. According to the above criteria, MRI plain scan images of 350 patients with rectal cancer and positive CRM in The Affiliated Hospital of Qingdao University from July 2016 to June 2019 were collected. The patients were classified by gender and tumor position, and randomly assigned to the training group (300 cases) and the validation group (50 cases) at a ratio of 6:1 by computer random number method. The CRM positive region was identified on the T2WI image using the LabelImg software. The identified training group images were used to iteratively train and optimize parameters of the Faster R-CNN model until the network converged to obtain the best deep learning model. The test set data were used to evaluate the recognition performance of the artificial intelligence platform. The selected indicators included accuracy, sensitivity, positive predictive value, receiver operating characteristic (ROC) curves, areas under the ROC curves (AUC), and the time taken to identify a single image. Results: The accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of the CRM status determined by the trained Faster R-CNN artificial intelligence approach were 0.884, 0.857, 0.898, 0.807, and 0.926, respectively; the AUC was 0.934 (95% CI: 91.3% to 95.4%). The Faster R-CNN model's automatic recognition time for a single image was 0.2 s. Conclusion: The artificial intelligence model based on Faster R-CNN for the identification and segmentation of CRM-positive MRI images of rectal cancer is established, which can complete the risk assessment of CRM-positive areas caused by in-situ tumor invasion and has the application value of preliminary screening.

The utility of longitudinal slicing method for rectal specimen: pathological analysis of circumferential resection margin of intersphincteric resection for low-lying rectal cancer.

The pathological assessment of the resection margin of rectal cancer is important to predict clinical outcome. The transverse slicing method of rectal specimens is recommended in Western countries. However, in Japan the longitudinal slicing method is traditionally advocated. The aim of this study was to assess the advantages of the longitudinal slicing method. The subjects were 197 consecutive patients with primary rectal cancer who underwent curative intersphincteric resection from 2000 to 2013. The resected rectal specimens were cut into 12 slices in the direction of the long axis. Resection margin was considered positive when it was less than or equal to 1 mm. Resection margin was positive in 23 patients (12%). They were classified into two groups, namely the DEEP group (n = 16, 70%), when the resection margin corresponded to the deepest tumor invasion area, and the ENTRY group (n = 7, 30%), when resection margin was around the initial cutting point of the anal canal. It was shown that resection margin tends to be positive not only in the deepest tumor invasion area but also in the entry area of the anal canal. The longitudinal slicing method may have some advantages for accurate assessment of resection margin especially in low-lying rectal cancer.

Clinical effect of laparoscopic I-stage resection for colorectal liver metastasis

Objective To investigate the safety, feasibility and clinical effect of laparoscopic Ⅰ-stage resection of colorectal liver metastasis (CRLM). Methods The retrospective cohort study was adopted. The clinicopathological data of 11 patients who underwent laparoscopic Ⅰ-stage resection of CRLM at the Affiliated Tumor Hospital of Zhengzhou University from February 2012 to October 2015 were collected. The primary lesions were confirmed by preoperative colonoscopy, abdominal CT and pathological biopsy, and liver metastases were diagnosed by abdominal enhanced CT or MRI. Patients selected preoperative individualized adjuvant therapy according to their conditions, and then underwent laparoscopic Ⅰ-stage resection of CRLM. After operation, patients received adjuvant chemotherapy of FOLFOX6 (oxaliplatin+ calcium folinate+ fluorouracil) or FOLFRIRI (irinotecan+ calcium folinate+ fluorouracil) regimens. The pre-, intra- and post-operative indexes were recorded, including (1) location and diameter of tumor and preoperative treatment; (2) surgical method, volume of intraoperative blood loss, operation time, resection margin and number of lymph node dissected; (3) complications, result of pathological examination, time of gastrointestinal function recovery, time for diet intake, duration of hospital stay, adjuvant therapy and recurrence of tumor. Patients were followed up by outpatient examination and telephone interview. The regular reexaminations of tumor marker, ultrasound and abdominal CT were applied to patients for detecting the recurrence of tumor till November 2015. Measurement data with normal distribution and with skewed distribution were presented as ±s and M(range), respectively. Results (1)Preoperative indexes: ascending colon cancer was detected in 2 patients, descending colon cancer in 1 patient, sigmoid cancer in 2 patients and rectal cancer in 6 patients. There were 6 solitary liver metastases with tumor diameter of 2.0-5.0 cm and 5 multiple liver metastases with average tumor number of 2.4 and tumor diameter of 1.0-4.0 cm. Four patients underwent preoperative neoadjuvant chemotherapy and 1 with rectal cancer underwent neoadjuvant radiotherapy. (2) Intra-operative status: all the 11 patients received successful laparoscopic Ⅰ-stage resection of CRLM. Laparoscopic liver irregular wedge resection was performed in 7 patients, regular hepatic lobes resection in 4 patients, left hemicolec-tomy in 2 patients, right hemicolectomy in 2 patients, Miles operation in 4 patients and Dixon operation in 3 patients. The operation time and volume of intraoperative blood loss were (245±61)minutes and (400±277)mL, without the occurrence of uncontrollable bleeding. The distal and proximal resection margins of colorectal cancer specimens (R0 resection) and circumferential resection margin of rectal cancer were negative. The median number of lymph node dissected, positive lymph node, negative resection margin of liver tumor (R0 resection)and positive laparoscopic resection margin (R1 resection) were 16 (range, 11-27), 0 (range, 0-7), 10 and 1, respectively. (3) Postoperative status: 2 patients had postoperative complications including 1 with intra peritoneal effusion and 1 with intraperitoneal infection, without occurrence of bile leakage, abdominal bleeding, anastomotic leakage, subphrenic abscess and hepatic failure. The time of postoperative gastrointestinal function recovery, time for diet intake and duration of hospital stay were (3.0±0.6)days, (3.0±0.9)days and (11.0±4.0)days, respectively. All the 11 patients underwent adjuvant chemotherapy of FOLFOX6 regimen, and 1 of 11 patients changed FOLFOX6 regimen into FOLFRIRI regimen due to recurrence of liver metastases. All the patients were followed up for a median time of 17 months (range, 2-44 months). During the follow-up, 1 patient died of pulmonary, brain and abdominal metastases and 10 patients had survival without recurrence of tumor except 1 with recurrence of liver metastasis. Conclusion Laparoscopic Ⅰ-stage resection of CRLM is safe and feasible for eligible patients, with a satisfactory short-term outcome. Key words: Colorectal neoplasms; Liver metastases; Laparoscopy

PTH-311 The significance of a positive lymph node at the circumferential resection margin in rectal cancer – does it reduce survival?

<h3>Introduction</h3> It is recognised that following rectal cancer resection, a threatened or involved circumferential resection margin (CRM) is associated with increased local recurrence rates. However the significance of a pathological positive lymph node (LN) threatening or involving the CRM remains unclear. The aim of this study was to investigate whether a CRM threatened with a positive lymph node was as significant as for a threatened margin with tumour. The effect of a positive margin on local recurrence, distant recurrence, overall survival and disease-free survival is examined. <h3>Method</h3> From April 2005 to July 2013, a prospectively collected database was used, from a single pathologist with a particular interest in rectal cancer. Data was collected on patients with a threatened or involved CRM, defined as cancer within 1mm of the margin. Data was collected on demographics, type of surgery, lymph node yield, the type of CRM involvement (LN/tumour), local and distant recurrence (LR and DR), overall survival (OS) and disease-free survival (DFS). <h3>Results</h3> From a total of 303 patients, complete data was available for 280 patients: 195male, 86 female; median age 69 (range 23–89). 90 patients had APR and 191 anterior resection. Median LN yield was 41 (range 9–122) 33/281 patients (11.7%) had a positive margin: 16 patients had tumour at the CRM, 13 patients had involved LN and 4 patients involved nerve or blood vessels. Median follow-up was 30 months (range 0–80). In patients with a positive CRM, LR occurred in 6/33 (18.1%) (1 from LN and 5 from tumour) and DR in 12/33 (36.3%) (5 from LN and 7 from tumour). In patients with negative CRM, LR was 17/248 (6.9%) and DR was 26/248 (10.5%). Kaplan Meier predicted 3 and 5-year OS for negative CRM was 84.6 and 75.1% vs. 74.1% and 49.4% for LN at CRM versus 37.5% and 20.0% for tumour at CRM. OS was significantly lower for tumour at CRM than negative CRM (p = 0.001) but no significant difference for LN at CRM (p = 0.209). Kaplan Meier predicted 3 and 5-year DFS for negative CRM was 76.4% and 65.3% vs. 53.8% and 43.1% for LN at CRM versus 25% and 18.8%for tumour at CRM. DFS was significantly lower for tumour at CRM than negative CRM (p = 0.001) but no significant difference for LN at CRM (p = 0.075). <h3>Conclusion</h3> A positive LN at the CRM is not associated with high rates of local recurrence (8%) but did result in distant recurrence in 38% patients. OS and DFS were worse for patients with a positive CRM due to tumour at the margin compared with patients with a negative CRM. However, despite a trend towards lower survival, having a positive LN at the CRM is not associated with significantly reduced OS or DFS. <h3>Disclosure of interest</h3> None Declared.

Circumferential resection margin (CRM) positivity after MRI assessment and adjuvant treatment in 189 patients undergoing rectal cancer resection

The management of rectal cancer relies on accurate MRI staging. Multi-modal treatments can downstage rectal cancer prior to surgery and may have an effect on MRI accuracy. We aim to correlate the findings of MRI staging of rectal cancer with histological analysis, the effect of neoadjuvant therapy on this and the implications of circumferential resection margin (CRM) positivity following neoadjuvant therapy. An analysis of histological data and radiological staging of all cases of rectal cancer in a single centre between 2006 and 2011 were conducted. Two hundred forty-one patients had histologically proved rectal cancer during the study period. One hundred eighty-two patients underwent resection. Median age was 66.6 years, and male to female ratio was 13:5. R1 resection rate was 11.1%. MRI assessments of the circumferential resection margin in patients without neoadjuvant radiotherapy were 93.6 and 88.1% in patients who underwent neoadjuvant radiotherapy. Eighteen patients had predicted positive margins following chemoradiotherapy, of which 38.9% had an involved CRM on histological analysis. MRI assessment of the circumferential resection margin in rectal cancer is associated with high accuracy. Neoadjuvant chemoradiotherapy has a detrimental effect on this accuracy, although accuracy remains high. In the presence of persistently predicted positive margins, complete resection remains achievable but may necessitate a more radical approach to resection.

Prognostic Impact of Circumferential Resection Margin in Rectal Cancer Treated with Preoperative Chemoradiotherapy

The circumferential resection margin (CRM) is a strong prognostic factor in rectal cancer. The purpose of this study was to investigate the relationship between CRM distance and recurrence in patients with locally advanced rectal cancer who received preoperative chemoradiotherapy (CRT). We analyzed data for 561 patients who underwent preoperative CRT and curative surgery for locally advanced rectal cancer between August 2001 and December 2008. CRM was divided into four groups: group 1, CRM > 2 mm; group 2, 1.1-2.0 mm; group 3, 0.1-1.0 mm; and group 4, 0 mm. We assessed the associations of CRM with local recurrence and disease-free survival. Groups 1, 2, 3, and 4 comprised 487, 36, 20, and 18 patients, respectively. The local recurrence rate was highest and the disease-free survival rate was lowest in group 4, followed by groups 3, 2, and 1. Survival was similar between groups 2 and 1. Local recurrence rates were lower in groups 3, 2, and 1 than in group 4 [hazard ratio (HR) 0.28, 95 % confidence interval (CI) 0.09-0.91, P = 0.035; HR 0.11, 95 % CI 0.03-0.46, P = 0.002; HR 0.18, 95 % CI 0.08-0.42, P < 0.0001, respectively]. Disease-free survival rates were higher in groups 3, 2, and 1 than in group 4 (HR 0.32, 95 % CI 0.13-0.75, P = 0.009; HR 0.24, 95 % CI 0.10-0.54, P = 0.001; HR 0.26, 95 % CI 0.14-0.48, P < 0.0001, respectively). After preoperative CRT, CRM distance provides useful information for risk stratification in the recurrence of rectal cancer.

Is the 1-cm Rule of Distal Bowel Resection Margin in Rectal Cancer Based on Clinical Evidence? A Systematic Review

Background Distal intramural spread is present within 1 cm from visible tumor in a substantial proportion of patients. Therefore, ≥1 cm of distal bowel clearance is recommended as minimally acceptable. However, clinical results are contradictory in answering the question of whether this rule is valid. The aim of this review was to evaluate whether in patients undergoing anterior resection, a distal bowel gross margin of <1 cm jeopardizes oncologic safety.

Adequate length of the surgical Distal resection margin in rectal cancer: from the viewpoint of pathological findings

BackgroundPrevious studies have not identified how to determine the optimal distal margin in rectal cancer based on histopathological diagnosis. We examined the surgical distal resection margin from a histopathological viewpoint. MethodsWe enrolled 629 patients. The type of distal spread was evaluated, and the maximum length of distal spread was measured using a micrometer. ResultsThe frequencies of discontinuous spread type were 1.0%, 8.4%, 52.9%, and 81.5%, and the average lengths of distal spread were .5 ± 1.3 mm, 7 ± 1.8 mm, 2.7 ± 2.4 mm, and 10.0 ± 9.5 mm for well-differentiated adenocarcinomas, moderately differentiated adenocarcinomas, solid (por1)-type poorly differentiated adenocarcinomas, and nonsolid (por2)-type poorly differentiated adenocarcinomas, (moderately vs solid [por1] type: P = .004), respectively. ConclusionsThe surgical distal resection margin based on pathological diagnosis is longer somewhat than that based on macroscopic findings. Therefore, it is important to select surgical procedures with great care to ensure an adequate surgical distal resection margin.

Is the 1-cm Rule of Distal Bowel Resection Margin in Rectal Cancer Based on Clinical Evidence? A Systematic Review

BackgroundDistal intramural spread is present within 1 cm from visible tumor in a substantial proportion of patients. Therefore, ≥1 cm of distal bowel clearance is recommended as minimally acceptable. However, clinical results are contradictory in answering the question of whether this rule is valid. The aim of this review was to evaluate whether in patients undergoing anterior resection, a distal bowel gross margin of <1 cm jeopardizes oncologic safety.MethodsA systematic review of the literature identified 17 studies showing results in relation to margins of approximately <1 cm (948 patients) versus >1 cm (4626 patients); five studies in relation to a margin of ≤5 mm (173 patients) versus >5 mm (1277 patients), and five studies showing results in a margin of ≤2 mm (73 patients). In most studies, pre- or postoperative radiation was provided.ResultsA multifactorial process was identified resulting in selection of favorable tumors for anterior resection with the short bowel margin and unfavorable tumors for abdominoperineal resection or for anterior resection with the long margin. In total, the local recurrence rate was 1.0% higher in the <1-cm margin group compared to the >1-cm margin group (95% confidence interval [CI] −0.6 to 2.7; P = 0.175). The corresponding figures for ≤5 mm cutoff point were 1.7% (95% CI −1.9 to 5.3; P = 0.375). The pooled local recurrence rate in patients having ≤2 mm margin was 2.7% (95% CI 0 to 6.4).ConclusionsIn the selected group of patients, <1 cm margin did not jeopardize oncologic safety.

P52 3T MRI determination of circumferential resection margin in rectal cancer – Correlation with histopathology

P52 3T MRI determination of circumferential resection margin in rectal cancer – Correlation with histopathology

MRI criterion for prediction of involvement of circumferential resection margin in rectal cancer

MRI criterion for prediction of involvement of circumferential resection margin in rectal cancer

Can CT Replace MRI in Preoperative Assessment of the Circumferential Resection Margin in Rectal Cancer?

The surgical circumferential resection margin in total mesorectal excision surgery is defined by the relationship of the tumor to the mesorectal fascia. Patients with anticipated tumor invasion of the mesorectal fascia receive neoadjuvant therapy to downstage/downsize the tumor and to obtain tumor-free resection margins.Tumor relationship to the mesorectal fascia is accurately determined by MRI. Compared with MRI, multidetector-row computed tomography is more widely available, faster, less costly, and provides the ability to simultaneously assess the liver, peritoneum, and retroperitoneum for metastases. The objective of this study was to compare the accuracy of multidetector-row CT with conventional MRI in diagnosis of rectal cancer invasion of the mesorectal fascial envelope. During a 2-year period, all patients were enrolled in this study who had biopsy-proven rectal carcinoma and were referred, as a part of the routine preoperative staging workup, for a CT scan of the abdomen and pelvis and also an MRI of the pelvis.All examinations were reviewed independently by 2 radiologists who were blinded from one another, from the findings of the other modality, and from clinical information. Both observers were dedicated abdominal radiologists who are experienced in reading pelvic CT and MRI. Categorical agreement between MRI and multidetector-row CT for all the evaluated parameters of the tumor position, mesorectal fascia, and lymph nodes, as well as the interobserver agreement between CT and MRI, was determined by the intraclass correlation weighted kappa statistic to measure the data set's consistency. Among the study's 92 patients, the tumor characteristics suggested by multidetector-row CT agreed with those of MRI, with a weighted kappa ranging from 0.488 to 0.748 for the first reader and 0.577 to 0.800 for the second reader. Interobserver agreement ranged from 0.506 to 0.746.Agreement regarding mesorectal fascia characteristics differed significantly between multidetector-row CT and MRI, depending on the level of assessment. In the distal rectum, agreement was 0.207 for the first reader and 0.385 for the second reader. In the mid rectum, agreement was 0.420 and 0.527, respectively, and in the proximal rectum agreement was 0.508 and 0.520. Interobserver agreement was 0.737 at the distal level and 0.700 at the mid and proximal levels. Agreement regarding measurement of the distance from the tumor to the mesorectal fascia was 0.425 for the first reader and 0.723 for the second reader, with interobserver agreement of 0.766. Agreement in assessment of the number of lymph nodes ranged from 0.743 to 0.787 for the first reader and 0.754 to 0.840 for the second reader. Interobserver agreement ranged from 0.779 to 0.841. Agreement in assessment of the size of the lymph nodes ranged from 0.540 to 0.830 for the first reader and 0.850 to 0.940 for the second reader. Interobserver agreement ranged from 0.900 to 0.920. Agreement in assessment of the distance from nodes to the mesorectal fascia was 0.320 for the first reader and 0.401 for the second reader, with interobserver agreement of 0.950. The results of this study differ from previously published data by demonstrating substantial agreement between readers in multidetector-row CT assessment of the tumor, mesorectal fascia, and lymph nodes. With the exceptions of mesorectal fascia in the distal rectum and the distance from the nodes to mesorectal fascia, other evaluated parameters were assessed with moderate and substantial agreement between multidetector-row CT and MRI. However, our findings suggest that multidetector-row CT does not correlate well enough with MRI findings to replace it in rectal cancer staging.

Expressions of connexin and par-3 in the distal margin of rectal cancer after ultra-low anterior resection

This study examined the expression of connexin and protease-activated receptor 3 (par-3) in the distal resection margin of rectal cancer and the correlation of the expression of the two proteins with tumor relapse. A total of 40 patients with rectal cancer underwent ultra-low anterior resection with curved cutter stapler. The pathological specimens were divided into 3 groups in terms of sampling sites: tumor group, 2.0-cm group (in which the tissues were harvested 2.0 cm distal to the tumor tissues), 3.0-cm group (in which the tissues were taken 3.0 cm away from the tumor tissues). All the samples were pathologically observed and then measured for the expression of connexin and par-3 by employing immunohistochemistry and Western blotting. The operations in this series went uneventfully. No anastomotic stoma bleeding, stenosis and death occurred postoperatively. Histopathologically, in the tumor group, epithelial cells lost normal pattern of arrangement and polarity, and were loosely connected and even detached. In the 3.0-cm group, the epithelia had normal appearance, obvious cell polarity and essentially intact cell junction. Immunohistochemistry and Western blotting indicated that the 3.0-cm group had the strongest expression of connexin and par-3, and the expression in the 2.0-cm group and the tumor group was relatively weak. There existed significant difference in the expression of the two proteins among the three groups (P<0.05 for all). It was concluded that the down-regulated connexin and par-3 in the distal margin of rectal cancer tissues may indicate the progression of the disease and high likelihood of recurrence and metastasis. Although no tumor cells were found in the sections of the 2.0-cm group, the decreased expression of connexin and par-3 may suggest the development of anaplasia and the increased odds of tumor relapse. Therefore, we are led to speculate that tumor resection only including 2.0 cm of unaffected rectum could not completely avoid the distant metastasis and local relapse.

Accuracy of preoperative magnetic resonance imaging in prediction of pathological stage and circumferential resection margin in rectal cancer

To evaluate the accuracy of preoperative magnetic resonance imaging (MRI) in prediction of pathological staging and involvement of circumferential resection margin (CRM) in rectal cancer. Fifty-three patients undergoing total mesorectal excision for biopsy-proven rectal cancer were assessed prospectively using high-resolution MRI for tumour (T) and mesorectal nodal (N) staging as well as CRM status using the depth of tumour spread, tumour node metastasis and CRM involvement. Preoperative MRI assessment of these prognostic factors was compared with the histopathological findings in carefully matched whole-mount sections of the specimen. MRI correctly staged the tumor in 41 patients, understaged in 8, and overstaged in 4. The accuracy of T stage was 77.4% (41/53). There was ageneric correlation between pathologic and MRI tumor staging (Kappa = 0.602, P < 0.001). Node status was correctly staged in 37 patients, overstaged in 10, and understaged in 6. The accuracy of node staging was 69.8% (37/53), sensitivity was 75% (18/24), and specificity was 65.5% (19/29). The correlation between pathologic and MRI node staging was poor (Kappa = 0.399, P = 0.003). The CRM status was correctly reported in 51 patients, overstaged in 1, and understaged in 1. The accuracy of CRM status was 96.2% (51/53), sensitivity was 80% (1/5), and specificity was 97.9% (47/48). There was a good correlation between pathologic and MRI CRM involvement (Kappa = 0.779, P < 0.001). Preoperative MRI provides poor predictive data as to subsequent pathologic tumor and mesorectal node stage, but does produce reliable prediction of clear CRM.

Laparoscopic Total Mesorectal Excision for Rectal Cancers

Introduction: More and more colorectal surgeons believe that total mesorectal excision can achieve favorable oncologic results for the treatment of rectal cancers. The present study is a feasibility study aiming to evaluate if total mesorectal excision can be safely performed by laparoscopic approach with beneficial functional recovery. Methods: A total of 44 patients (from January 2004 to February 2005) with middle rectal cancer (the average distance from anal verge was 7.8 cm, ranging from 5.0 to 10.0 cm) without preoperative chemoradiation therapy were selected to undergo laparoscopic total mesorectal excision. Before the study entry, all patients underwent pelvic magnetic resonance imaging or multislice spiral computed tomography to evaluate the circumferential resection margin of rectal cancer. Only patients whose circumferential resection margin was not involved by rectal cancer were considered as potentially curable by total mesorectal excision procedures and were enrolled for this study. The operation procedures were conducted according to the guidelines advocated by Healdet al.1 and were shown in the video. Posteriorly, the dissection was along the ‘holy plane' downward to the level of levator ani muscle. Anteriorly, the dissection plane was at the anterior part of Denonvilliers fascia. Laterally, the lateral ligaments were sharply cauterized at the medial part. The resected bowel was reconstructed with stapled end-to-end anastomosis. The surgical outcomes of this procedure were prospectively evaluated. Results: The laparoscopic total mesorectal excision was performed with acceptable operation time (234.4±44.4 minutes, mean±standard deviation) and little blood loss (80.0±24.0 ml) through a small wound (5.0±0.5 cm). Histopathology showed that all patients were able to get adequate distal section margins (mean: 2.8 cm; range: 1.6-5.4 cm) and negative circumferential resection margins (mean: 8.4mm; range: 2-14 mm). The number of dissected lymph nodes was 16.0±4.0. The pathologic tumor-node-metastasis stages were as follows: Stage I: n= 4; Stage II: n = 22; Stage III: n = 18. Two patients (4.5 percent) were diverted by protective ileostomy. There was no mortality within 30 days after operation. However, anastomotic leakage occurred in 3 patients. The patients have quick functional recovery, as evaluated by the length of postoperative ileus (48.0±12.0 hours), hospitalization (9.0±1.0 days) and degree of postoperative pain (3.5±0.5, visual analog scale). Besides the expenses covered by the National Bureau of Health Insurance in Taiwan, the patient had to pay an extra expense of NT$ 65000.08000.0 (1.0US dollars = 32.0 NT$). During the follow-up periods (median: 14 months, range. 2 to 27 months), three patients of Stage III and 1 patient of Stage II developed a recurrent disease (lung metastasis: n = 2; liver metastasis: n = 1, and pelvic recurrence, n = 1). Conclusion: By laparoscopic approach, the total mesorectal excision for rectal cancers can be safely performed with good functional recovery. However, with only a median follow-up of 14 months in this case series, the long-term oncologic outcomes for these patients remain a question. Further randomized prospective study is thus mandatory to provide solid evidence of this approach.

Imaging for Predicting the Risk Factors—the Circumferential Resection Margin and Nodal Disease—of Local Recurrence in Rectal Cancer: A Meta-Analysis

The aim of the present study was to conduct a meta-analysis of English literature on the accuracy of preoperative imaging in predicting the two most important risk factors for local recurrence in rectal cancer, the circumferential resection margin (CRM) and the nodal status (N-status). Articles published between 1985 and August 2004 that report on the diagnostic accuracy of endoluminal ultrasound (EUS), computed tomography (CT), or magnetic resonance imaging (MRI) in the evaluation of lymph node involvement were included. A similar search was done for the assessment of the circumferential resection margin in rectal cancer in the period from January 1985 till January 2005. The inclusion criteria were as follows: (1) more than 20 patients with histologically proven rectal cancer were included, (2) histology was used as the gold standard, and (3) results were given in a 2 x 2 contingency table or this table could otherwise be extracted from the article by two independent readers. Based on the results summary receiver operating characteristic (ROC) curves were constructed. Only 7 articles matching inclusion criteria were found concerning the CRM. The meta-analysis shows that MRI is rather accurate in diagnosing a close or involved CRM. For nodal status 84 articles could be included. The diagnostic odds ratio of EUS is estimated at 8.83. For MRI and CT, the diagnostic odds ratio are 6.53 and 5.86, respectively. The results show that EUS is slightly, but not significantly, better than MRI or CT for identification of nodal disease. There is no significant difference between the different modalities with respect to staging nodal status. At present, MRI is the only modality that predicts the circumferential resection margin with good accuracy, making it a good tool to identify high and low risk patients. Predicting the N-status remains a problem for the radiologist for every modality, although considering the new developments in MR imaging, this may change in the near future.