Does circumferential tumor location affect the circumferential resection margin status in mid and low rectal cancer?

A Comprehensive Prediction Model Based on MRI Radiomics and Clinical Factors to Predict Tumor Response After Neoadjuvant Chemoradiotherapy in Rectal Cancer

RATIONALE AND OBJECTIVES

To establish a prediction model for the efficacy of neoadjuvant chemoradiotherapy (nCRT) in patients with locally advanced rectal cancer (LARC), using pretreatment magnetic resonance imaging (MRI) multisequence image features and clinical parameters.

MATERIALS AND METHODS

Patients with clinicopathologically confirmed LARC were included (training and validation datasets, n = 100 and 27, respectively). Clinical data of patients were collected retrospectively. We analyzed MRI multisequence imaging features. The tumor regression grading (TRG) system proposed by Mandard et al was adopted. Grade 1-2 of TRG was a good response group, and grade 3-5 of TRG was a poor response group. In this study, a clinical model, a single sequence imaging model, and a comprehensive model combined with clinical imaging were constructed, respectively. The area under the subject operating characteristic curve (AUC) was used to evaluate the predictive efficacy of clinical, imaging, and comprehensive models. The decision curve analysis method evaluated the clinical benefit of several models, and the nomogram of efficacy prediction was constructed.

RESULTS

The AUC value of the comprehensive prediction model is 0.99 in the training data set and 0.94 in the test data set, which is significantly higher than other models. Radiomic Nomo charts were developed using Rad scores obtained from the integrated image omics model, circumferential resection margin(CRM), DoTD, and carcinoembryonic antigen(CEA). Nomo charts showed good resolution. The calibrating and discriminating ability of the synthetic prediction model is better than that of the single clinical model and the single sequence clinical image omics fusion model.

CONCLUSION

Nomograph, based on pretreatment MRI characteristics and clinical risk factors, has the potential to be used as a noninvasive tool to predict outcomes in patients with LARC after nCRT.

International standardization and optimization group for intersphincteric resection (ISOG-ISR): modified Delphi consensus on anatomy, definition, indication, surgical technique, specimen description and functional outcome

AIM

Intersphincteric resection (ISR) is an oncologically complex operation for very low-lying rectal cancers. Yet, definition, anatomical description, operative indications and operative approaches to ISR are not standardized. The aim of this study was to standardize the definition of ISR by reaching international consensus from the experts in the field. This standardization will allow meaningful comparison in the literature in the future.

METHOD

A modified Delphi approach with three rounds of questionnaire was adopted. A total of 29 international experts from 11 countries were recruited for this study. Six domains with a total of 37 statements were examined, including anatomical definition; definition of intersphincteric dissection, intersphincteric resection (ISR) and ultra-low anterior resection (uLAR); indication for ISR; surgical technique of ISR; specimen description of ISR; and functional outcome assessment protocol.

RESULTS

Three rounds of questionnaire were performed (response rate 100%, 89.6%, 89.6%). Agreement (≥80%) reached standardization on 36 statements.

CONCLUSION

This study provides an international expert consensus-based definition and standardization of ISR. This is the first study standardizing terminology and definition of deep pelvis/anal canal anatomy from a surgical point of view. Intersphincteric dissection, ISR and uLAR were specifically defined for precise surgical description. Indication for ISR was determined by the rectal tumour's maximal radial infiltration (T stage) below the levator ani. A new surgical definition of T3isp was reached by consensus to define T3 low rectal tumours infiltrating the intersphincteric plane. A practical flowchart for surgical indication for uLAR/ISR/abdominoperineal resection was developed. A standardized ISR surgical technique and functional outcome assessment protocol was defined.

Morphology of the anterior mesorectum: a new predictor for local recurrence in patients with rectal cancer

BACKGROUND

Pre-operative assessment with high-resolution magnetic resonance imaging (MRI) is useful for assessing the risk of local recurrence (LR) and survival in rectal cancer. However, few studies have explored the clinical importance of the morphology of the anterior mesorectum, especially in patients with anterior cancer. Hence, the study aimed to investigate the impact of the morphology of the anterior mesorectum on LR in patients with primary rectal cancer.

METHODS

A retrospective study was performed on 176 patients who underwent neoadjuvant treatment and curative-intent surgery. Patients were divided into two groups according to the morphology of the anterior mesorectum on sagittal MRI: (1) linear type: the anterior mesorectum was thin and linear; and (2) triangular type: the anterior mesorectum was thick and had a unique triangular shape. Clinicopathological and LR data were compared between patients with linear type anterior mesorectal morphology and patients with triangular type anterior mesorectal morphology.

RESULTS

Morphometric analysis showed that 90 (51.1%) patients had linear type anterior mesorectal morphology, while 86 (48.9%) had triangular type anterior mesorectal morphology. Compared to triangular type anterior mesorectal morphology, linear type anterior mesorectal morphology was more common in females and was associated with a higher risk of circumferential resection margin involvement measured by MRI (35.6% [32/90] vs . 16.3% [14/86], P   =  0.004) and a higher 5-year LR rate (12.2% vs . 3.5%, P   =  0.030). In addition, the combination of linear type anterior mesorectal morphology and anterior tumors was confirmed as an independent risk factor for LR (odds ratio = 4.283, P  = 0.014).

CONCLUSIONS

The classification established in this study was a simple way to describe morphological characteristics of the anterior mesorectum. The combination of linear type anterior mesorectal morphology and anterior tumors was an independent risk factor for LR and may act as a tool to assist with LR risk stratification and treatment selection.

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.

Impact of circumferential tumor location of mid to low rectal cancer on oncologic outcomes after preoperative chemoradiotherapy

Purpose

Some studies have suggested that circumferential tumor location (CTL) of rectal cancer may affect oncological outcomes. However, studies after preoperative chemoradiotherapy (CRT) are rare. This study aimed to evaluate the impact of CTL on oncologic outcomes of patients with mid to low rectal cancer who received preoperative CRT.

Methods

Patients with mid to low rectal cancer who underwent total mesorectal excision after CRT from January 2013 to December 2018 were included in this retrospective study. The impact of CTL on the pathological circumferential resection margin (CRM) status, local recurrence-free survival (LRFS), disease-free survival (DFS), and overall survival (OS) was analyzed.

Results

Of the 381 patients, 98, 70, 127, and 86 patients were categorized into the anterior, posterior, lateral, and circumferential tumor groups, respectively. Tumor location was not significantly associated with the pathological CRM involvement (anterior, 12.2% vs. posterior, 14.3% vs. lateral, 11.0% vs. circumferential, 17.4%; P = 0.232). Univariate analyses revealed no correlation between CTL and 3-year LRFS (93.0% vs. 89.1% vs. 91.5% vs. 88%, P = 0.513), 3-year DFS (70.3% vs. 70.2% vs. 75.3% vs. 75.7%, P = 0.832), and 5-year OS (74.7% vs. 78.0% vs. 83.9% vs. 78.2%, P = 0.204). Multivariate analysis identified low rectal cancer and pathological CRM involvement as independent risk factors for all survival outcomes (all P < 0.05).

Conclusion

CTL of rectal cancer after preoperative CRT was not significantly associated with the pathological CRM status, recurrence, and survival.

Effect of Tumor Location on Outcome After Laparoscopic Low Rectal Cancer Surgery: A Propensity Score Matching Analysis

BACKGROUND

Dissection of the distal anterolateral aspect of the mesorectum remains a surgical challenge for low rectal cancer, posing a higher risk of residual mesorectum, which might lead to the increased incidence of local recurrence for patients with anterior wall involvement.

OBJECTIVE

This study aimed to assess the effect of tumor location on outcome after laparoscopic low rectal cancer surgery.

DESIGN

This is a single-center, retrospective study.

SETTINGS

The study was conducted at West China Hospital in China.

PATIENTS

Patients with low rectal cancer who underwent laparoscopic total mesorectal excision from 2011 to 2016 were enrolled. Patients were divided into anterior and nonanterior groups according to tumor location. Propensity score matching analysis was used to reduce the selection bias.

MAIN OUTCOME MEASURES

The primary end point was local recurrence. The secondary end points included overall survival, disease-free survival, and the positive rate of circumferential resection margin.

RESULTS

A total of 404 patients were included, and 176 pairs were generated by propensity score matching analysis. Multivariate analysis showed that anterior location was an independent risk factor of local recurrence (HR, 12.6; p = 0.006), overall survival (HR, 3.0; p < 0.001), and disease-free survival (HR, 2.3; p = 0.001). For patients with clinical stage II/III or T3/4, anterior location remained a prognostic factor for higher local recurrence and poorer survival. Local recurrence was rare in patients with clinical stage II/III (1.4%) or T3/4 (1.5%) tumors that were not located anteriorly.

LIMITATIONS

This study was limited by its retrospective nature.

CONCLUSIONS

Anterior location is an independent risk factor of local recurrence, overall survival, and disease-free survival for low rectal cancer. More strict and selective use of neoadjuvant therapy should be considered for patients who have clinical stage II/III or T3/4 tumors that are not located anteriorly. A larger cohort study is warranted to validate the prognostic role of anterior location for low rectal cancer. See Video Abstract at http://links.lww.com/DCR/B622.

IMPACTO DE LA LOCALIZACIN DEL TUMOR EN EL RESULTADO POSTERIOR A CIRUGA LAPAROSCPICA DE CNCER DE RECTO INFERIOR UN PUNTAJE DE PROPENSIN POR ANLISIS DE CONCORDANCIA

ANTECEDENTES:La disección de la cara anterolateral distal del mesorrecto sigue siendo un desafío quirúrgico en el cáncer de recto inferior, constituyendo un alto riesgo de mesorrecto residual, que podría ocasionar una mayor incidencia de recurrencia local en pacientes con compromiso de la pared anterior.OBJETIVO:El objetivo del estudio fue evaluar el efecto de la localización del tumor en el resultado posterior a la cirugía laparoscópica de cáncer de recto inferior.DISEÑO:Estudio restrospectivo de un único centro.ÁMBITO:El estudio se realizó en el West China Hospital en China.PACIENTES:Pacientes con cáncer de recto inferior que se sometieron a excisión mesorrectal total laparoscópica entre 2011 y 2016. Los pacientes se dividieron en grupos, anterior y no anterior, según la localización del tumor. Se utilizó un puntaje de propensión por análisis de concordancia para reducir el sesgo de selección.PRINCIPALES VARIABLES EVALUADAS:El objetivo principal fue la recurrencia local. Los objetivos secundarios incluyeron la sobrevida global, la sobrevida libre de enfermedad y la tasa de positividad del margen de resección circunferencial.RESULTADOS:Se incluyeron un total de 404 pacientes y se generaron 176 pares mediante un puntaje de propensión por análisis de concordancia. El análisis multivariado mostró que la localización anterior era un factor de riesgo independiente de recidiva local (HR = 12,6, p = 0,006), sobrevida global (HR = 3,0, p <0,001) y sobrevida libre de enfermedad (HR = 2,3, p = 0,001). En pacientes con estadio clínico II /III o T3/4, la ubicación anterior continuó como un factor pronóstico para una mayor recurrencia local y una menor sobrevida. La recidiva local fue excepcional en pacientes con tumores en estadio clínico II / III (1,4%) o T3 / 4 (1,5%) que no estaban localizados hacia anterior.LIMITACIONES:Este estudio estuvo limitado por su carácter retrospectivo.CONCLUSIONES:La localización anterior es un factor de riesgo independiente de recidiva local, sobrevida global y sobrevida libre de enfermedad para el cáncer de recto inferior. Se debe considerar un uso más estricto y selectivo de la terapia neoadyuvante para pacientes en estadio clínico II / III o T3 /4 de tumores que no se localizan hacia anterior. Se justifica un estudio de cohorte más grande para validar el impacto pronóstico de una ubicación anterior del cáncer de recto inferior. Consulte Video Resumen en http://links.lww.com/DCR/B622. (Traducción-Dr. Lisbeth Alarcon-Bernes).

Anus-Preserving Surgery in Advanced Low-Lying Rectal Cancer: A Perspective on Oncological Safety of Intersphincteric Resection

The surgical management of low-lying rectal cancer, within 5 cm from the anal verge (AV), is challenging due to the possibility, or not, to preserve the anus with its sphincter muscles maintaining oncological safety. The standardization of total mesorectal excision, the adoption of neoadjuvant chemoradiotherapy, the implementation of rectal magnetic resonance imaging, and the evolution of mechanical staplers have increased the rate of anus-preserving surgeries. Moreover, extensive anatomy and physiology studies have increased the understanding of the complexity of the deep pelvis. Intersphincteric resection (ISR) was introduced nearly three decades ago as the ultimate anus-preserving surgery. The definition and indication of ISR have changed over time. The adoption of the robotic platform provides excellent perioperative results with no differences in oncological outcomes. Pushing the boundaries of anus-preserving surgeries has risen doubts on oncological safety in order to preserve function. This review critically discusses the oncological safety of ISR by evaluating the anatomical characteristics of the deep pelvis, the clinical indications, the role of distal and circumferential resection margins, the role of the neoadjuvant chemoradiotherapy, the outcomes between surgical approaches (open, laparoscopic, and robotic), the comparison with abdominoperineal resection, the risk factors for oncological outcomes and local recurrence, the patterns of local recurrences after ISR, considerations on functional outcomes after ISR, and learning curve and surgical education on ISR.

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

BACKGROUND

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.

OBJECTIVE

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.

DESIGN

This was a retrospective cohort study.

SETTINGS

The study was conducted using the National Cancer Database, 2011-2016.

PATIENTS

Adults who underwent proctectomy for pathologic stage I to III rectal adenocarcinoma were included.

MAIN OUTCOME MEASURES

Rate and predictors of positive circumferential resection margin, defined as resection margin ≤1 mm, were measured.

RESULTS

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).

LIMITATIONS

This was a retrospective cohort study with limited variables available for analysis.

CONCLUSIONS

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.

PREDICTORES PARA UN MARGEN POSITIVO DE RESECCIN CIRCUNFERENCIAL EN EL CNCER DE RECTO UNA AUDITORA VIGENTE DE LA BASE DE DATOS NACIONAL DE CANCER

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.

Development of a Joint Prediction Model Based on Both the Radiomics and Clinical Factors for Predicting the Tumor Response to Neoadjuvant Chemoradiotherapy in Patients with Locally Advanced Rectal Cancer

Purpose

Neoadjuvant chemoradiotherapy (nCRT) has become the standard treatment for locally advanced rectal cancer (LARC). However, the accuracy of traditional clinical indicators in predicting tumor response is poor. Recently, radiomics based on magnetic resonance imaging (MRI) has been regarded as a promising noninvasive assessment method. The present study was conducted to develop a model to predict the pathological response by analyzing the quantitative features of MRI and clinical risk factors, which might predict the therapeutic effects in patients with LARC as accurately as possible before treatment.

Patients and Methods

A total of 82 patients with LARC were enrolled as the training cohort and internal validation cohort. The pre-CRT MRI after pretreatment was acquired to extract texture features, which was finally selected through the minimum redundancy maximum relevance (mRMR) algorithm. A support vector machine (SVM) was used as a classifier to classify different tumor responses. A joint radiomics model combined with clinical risk factors was then developed and evaluated by receiver operating characteristic (ROC) curves. External validation was performed with 107 patients from another center to evaluate the applicability of the model.

Results

Twenty top image texture features were extracted from 6192 extracted-radiomic features. The radiomics model based on high-spatial-resolution T2-weighted imaging (HR-T2WI) and contrast-enhanced T1-weighted imaging (T1+C) demonstrated an area under the curve (AUC) of 0.8910 (0.8114–0.9706) and 0.8938 (0.8084–0.9792), respectively. The AUC value rose to 0.9371 (0.8751–0.9997) and 0.9113 (0.8449–0.9776), respectively, when the circumferential resection margin (CRM) and carbohydrate antigen 19-9 (CA19-9) levels were incorporated. Clinical usefulness was confirmed in an external validation cohort as well (AUC, 0.6413 and 0.6818).

Conclusion

Our study indicated that the joint radiomics prediction model combined with clinical risk factors showed good predictive ability regarding the treatment response of tumors as accurately as possible before treatment.

Risk factors for local recurrence and long term survival after minimally invasive intersphincteric resection for very low rectal cancer: Multivariate analysis in 161 patients

INTRODUCTION

Intersphincteric resection (ISR) is the ultimate anal-sparing technique as an alternative to abdominoperineal resection in selected patients. Oncological safety is still debated. This study analyses long-term oncological results and evaluates risk factors for local recurrence (LR) and overall survival (OS) after minimally-invasive ISR.

MATERIALS AND METHODS

Retrospective single-center data were collected from a prospectively maintained colorectal database. A total of 161 patients underwent ISR between 2008 and 2018. OS and local recurrence-free survival (LRFS) were assessed using Kaplan-Meier analysis (log-rank test). Risk factors for OS and LRFS were assessed with Cox-regression analysis.

RESULTS

Median follow-up was 55 months. LR occurred in 18 patients. OS and LRFS rates at 1, 3, and 5 years were 96%, 91%, and 80% and 96%, 89%, and 87%, respectively. Tumor size (p = 0.035) and clinical T-stage (p = 0.029) were risk factors for LRFS on univariate analysis. On multivariate analysis, tumor size (HR 2.546 (95% CI: 0.976-6.637); p = 0.056) and clinical T-stage (HR 3.296 (95% CI: 0.941-11.549); p = 0.062) were not significant. Preoperative CEA (p < 0.001), pathological T-stage (p = 0.033), pathological N-stage (p = 0.016) and adjuvant treatment (p = 0.008) were prognostic factors for OS on univariate analysis. Preoperative CEA (HR 4.453 (95% CI: 2.015-9.838); p < 0.001) was a prognostic factor on multivariate analysis.

CONCLUSIONS

This study confirms the oncological safety of minimally-invasive ISR for locally advanced low-lying rectal tumors when performed in experienced centers. Despite not a risk factor for LR, tumor size and, locally advanced T-stage with anterior involvement should be carefully evaluated for optimal surgical strategy. Preoperative CEA is a prognostic factor for OS.

Rectoseminal vesicle fistula after radical surgery for rectal cancer: Four case reports and a literature review

BACKGROUND

A rectoseminal vesicle fistula (RSVF) is a rare complication after anterior or low anterior proctectomy for rectal cancer mainly due to anastomotic leakage (AL). Limited literature documenting this rare complication is available. We report four such cases and review the literature to investigate the etiology, clinical manifestations, and the diagnostic and treatment methods of RSVF in order to provide greater insight into this disorder.

CASE SUMMARY

Four cases of RSVF were presented and summarized, and a further 12 cases selected from the literature were discussed. The main clinical symptoms in these patients were pneumaturia, fever, scrotal swelling and pain, anal pain, orchitis, diarrhea, dysuria, epididymitis and fecaluria. Imaging methods such as pelvic X-ray, computed tomography (CT), sinus radiography, barium enema and other techniques confirmed the diagnosis. CT was the imaging modality of choice. In cases presenting with reduced levels of AL, minimal surrounding inflammation, and controlled infection, the RSVF was conservatively treated by urethral catheterization, antibiotics administration and parenteral nutrition. In cases of severe RSVF, incision and drainage of the abscess or fistula and urinary or fecal diversion surgery successfully resolved the fistula.

CONCLUSION

This study provides an extensive analysis of RSVF, and outlines, summarizes and examines the causes, clinical manifestations, diagnostic procedures and treatment options, in order to prevent misdiagnosis and treatment errors.

Can Post-Treatment MRI Features Predict Pathological Circumferential Resection Margin (pCRM) Involvement in Low Rectal Tumors

The MERCURY II study demonstrated the use of MRI-based risk factors such as extramural venous invasion (EMVI), tumor location, and circumferential resection margin (CRM) involvement to preoperatively predict pCRM (pathological CRM) outcomes for lower rectal tumors in a mixed group of upfront operated patients and patients who received neoadjuvant treatment. We aim to study the applicability of results of MERCURY II study in a homogeneous cohort of patients who received neoadjuvant chemoradiation (NACTRT) prior to surgery. After Institutional Review Board approval, post NACTRT restaging MRI of 132 patients operated for low rectal cancer between 2014 and 2018 were retrospectively reviewed by two radiologists for site of tumor, EMVI status, distance from anal verge (< 4 or > 4 cm), and mrCRM positivity. Findings were compared with post surgery pCRM outcomes using Fisher's exact test. Only 9/132(7%) patients showed pCRM involvement on histopathology, 8 of them being CRM positive on MRI (p = 0.01). The positive predictive value (PPV) of mrCRM positive status and pCRM status was 12.7% (95% CI: 9.7-16.5%), while the negative predictive value was 98.5% (95% CI: 91.4-99.8%) (p = 0.01). EMVI positive and anteriorly located tumors showed higher incidence of pCRM positivity but were not found to be significant (15% vs 5.2% and p = 0.13 and 8.6% vs 2.1% and p = 0.28, respectively). Unsafe mrCRM was the only factor significantly associated with pCRM positivity on post neoadjuvant restaging MRI. Tumors less than 4 cm from anal verge, anterior tumor location, and mrEMVI positivity did not show statistically significant results to predict pCRM involvement.

Preoperative predictive risk to cancer quality in robotic rectal cancer surgery

BACKGROUND

Circumferential resection margin (CRM) involvement is widely considered the strongest predictor of local recurrence after TME. This study aimed to determine preoperative factors associated with a higher risk of pathological CRM involvement in robotic rectal cancer surgery.

METHODS

This was a retrospective review of a prospectively maintained database of consecutive adult patients who underwent elective, curative robotic low anterior or abdominoperineal resection with curative intent for primary rectal adenocarcinoma in a tertiary referral cancer center from March 2012 to September 2019. Pretreatment magnetic resonance imaging (MRI) reports were reviewed for all the patients. Risk factors for pathological CRM involvement were investigated using Firth's logistic regression and a predictive model based on preoperative radiological features was formulated.

RESULTS

A total of 305 patients were included, and 14 (4.6%) had CRM involvement. Multivariable logistic regression found both T3 >5 mm (OR 6.12, CI 1.35-36.44) and threatened or involved mesorectal fascia (OR 4.54, CI 1.33-17.55) on baseline MRI to be preoperative predictors of pathologic CRM positivity, while anterior location (OR 3.44, CI 0.72-33.13) was significant only on univariate analysis. The predictive model showed good discrimination (area under the receiver-operating characteristic curve >0.80) and predicted a 32% risk of positive CRM if all risk factors were present.

CONCLUSION

Patients with pre-operatively assessed threatened radiological margin, T3 tumors with greater than 5 mm extension and anterior location are at risk for a positive CRM. The predictive model can preoperatively estimate the CRM positivity risk for each patient, allowing surgeons to tailor management to improve oncological outcomes.

Correlation Between Endorectal Ultrasound and Magnetic Resonance Imaging for Predicting the Circumferential Resection Margin in Patients With Mid-Low Rectal Cancer Without Preoperative Chemoradiotherapy

OBJECTIVES

To assess the correlation between endorectal ultrasound (ERUS) and magnetic resonance imaging (MRI) in predicting the circumferential resection margin (CRM) status of patients with mid-low rectal cancer without preoperative chemoradiotherapy.

METHODS

Twenty patients with rectal cancer who did not receive preoperative chemoradiotherapy and underwent ERUS and MRI examinations before total mesorectal excision from May 2018 to April 2019 were included in this study. The patient and tumor characteristics, lymph nodes, tumor stages, ERUS and MRI predictors of the CRM status, and postoperative pathologic results were recorded. The closest distance between the deepest portion of lesion invasion and the mesorectal fascia was independently measured on MRI and ERUS images by 2 observers. The observers were blinded to the pathologic results. Measurements from ERUS and MRI were compared.

RESULTS

The mean distance between the distal edge of the lesion and the anal verge was 5.7 cm (range, 3.1-8.1 cm). The ERUS and pathologic evaluations of CRM involvement were consistent in 90% of the cases. The MRI and pathologic evaluations of CRM involvement were concordant in 95% of the cases. The Cohen κ coefficient of ERUS and MRI was 0.608 (P = .007). The correlation coefficient of ERUS and MRI for assessing the closest distance from the edge of cancer invasion to the mesorectal fascia was 0.99 (P = .0005).

CONCLUSIONS

Endorectal ultrasound and MRI assessments of the preoperative CRM status appear to be highly consistent. Endorectal ultrasound can be used as a complementary tool with MRI to predict the CRM status of patients with mid-low rectal cancer without preoperative chemoradiotherapy.

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.