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. (AU)
Subject(s)
Humans , Male , Female , Adult , Middle Aged , Aged , Rectal Neoplasms/surgery , Margins of Excision , Pelvimetry , Retrospective StudiesABSTRACT
La Resonancia Magnética de alta resolución (RM AR) es el mejor método para demostrar la relación del tumor rectal con el potencial margen circunferencial de resección quirúrgico. Por esta razón es considerada en la actualidad el método de elección en la estadificación local del cáncer de recto. La cirugía primaria del cáncer rectal es la escisión total del mesorrecto (ETM), cuyo plano de disección está formado por la fascia mesorrectal que envuelve la grasa del mesorrecto y al recto. Esta fascia es la que determinará el margen circunferencial de resección (MCR). Asu vez, la RM AR permite una adecuada identificación preoperatoria de importantes factores pronósticos de riesgo, mejorando la selección e indicación de la terapia para cada paciente. Esta información incluye, además del MCR, la estadificación tumoral y ganglionar, la invasión vascular extramural y la descripción de tumores de recto inferior. Todos ellos deberán ser descriptos minuciosamente en el informe, siendo parte importante de la discusión en el equipo multidisciplinario (EMD), ámbito en el cual se tomarán las decisiones que involucren al paciente con cáncer de recto. El objetivo de este trabajo es aportar la información necesaria para entender el uso de la RM AR en la identificación de los factores pronósticos de riesgo en el cáncer de recto. Se describirán los requerimientos técnicos para la realización de este estudio y el informe estandarizado, como así también los reparos anatómicos de importancia para la ETM, que como hemos dicho es la cirugía de elección en el cáncer de recto.
High-resolution MRI is the best method of assessing therelation of the rectal tumor with the potential circumferentialresection margin (CRM). Therefore it is currently considered the method of choice for local staging of rectal cancer. The primary surgery of rectal cancer is total mesorectal excision (TME), which plane of dissection is formed by the mesorectal fascia surrounding mesorectal fat and rectum. This fascia will determine the circumferential margin of resection. At the same time, high resolution MRI allows adequate pre-operative identification of important prognostic risk factors, improving the selection and indication of therapy for each patient. This information includes, besides the circumferential margin of resection, tumor and lymph node staging, extramural vascular invasion and the description of lower rectal tumors. All these should be described in detail in the report, being part of the discussion in the multidisciplinary team, the place where the decisions involving the patient with rectal cancer will take place. The aim of this study is to provide the information necessary to understand the use of high resolution MRI in the identification of prognostic risk factors in rectal cancer. The technical requirements and standardized report for this study will be describe, as well as the anatomical landmarks of importance for the total mesorectal excision (TME), as we have said is the surgery of choice for rectal cancer .
ABSTRACT
Propósito: Determinar si la RM puede predecir el compromiso tumoral del margen de resección circunferencial (MRC) en pacientes con cáncer de recto. Material y Métodos: Entre abril del 2005 y marzo del 2008, se evaluaron por resonancia magnética (RM), en forma consecutiva, 70 pacientes (40 M y 30 H, edad promedio de 64 años, rango de 34-78 años), con diagnóstico endoscópico y por biopsia de cáncer rectal inferior o medio. Se realizó una RM sin contraste E.V. en un equipo Siemens Avanto 1.5T, con bobina phase array de superficie. Se efectuaron secuencias con cortes finos ponderadas en T2 (TR¬-TE 4200-88, espesor de 3mm, gap 0, matriz de 256 x 256, FOV de 150x150 mm) en los planos axial, sagital y coronal. Los pacientes recibieron un enema rectal de 150 ml de glicerina previo al examen. No se realizó insuflación colónica ni administración de antiespasmódicos. Se midió la distancia más corta desde el borde del tumor hasta el MRC. Una distancia ≤ 2 mm en el plano axial se consideró como compromiso del MRC. Resultados: El MRC fue ≤ 2 mm tanto por RM como por anatomía patológica en 26 pacientes. En 8 casos, el MRC fue menor por RM que por anatomía patológica. En 32 pacientes el MRC estaba respetado por ambas metodologías diagnósticas y 4 pacientes fueron considerados positivos para compromiso del MRC en histología pero negativos por RM. La sensibilidad, especificidad, valor predictivo positivo y negativo de la RM para el compromiso tumoral del MRC fue de 86%, 80%, 76% y 88% respectivamente. Conclusión: La RM brinda información confiable del compromiso tumoral del MRC en pacientes con cáncer rectal, aportando una ayuda en la evaluación de este factor pronóstico de riesgo en pacientes previo al tratamiento quirúrgico.
Purpose: To determine whether magnetic resonance imaging (MRI) can predict tumor involvement of the circumferential resection margin (CRM) in patients with rectal cancer. Materials and methods: Between april 2005 and march 2008, 70 consecutive patients (mean age 64, range 34-78 years), 40 F and 30 M, with endoscopy and biopsy- proven middle and lower rectal cancer. Non contrast enhanced MRI was performed on a Siemens Avanto 1.5 T. A phased array coil was used and T2 weighted thin section sequences (TR/TE 4200/88, slice thickness 3mm, gap 0, matrix 256 x 256, field of view 150 x 150 mm) were performed in axial, sagittal and coronal orientations. Patients received a 150 ml glycerin enema before examination. No air insufflations or intramuscular antispasmodic was used. The shortest distance from the tumor edge to the circumferential margin was measured. A distance ≤ 2 mm, analyzed in axial slices, was considered as definition of circumferential margin involvement. Results: The CRM was 2 mm in both MRI and histopathological findings in 26 patients. In 8 cases the CRM was shorter on MRI than in histopathological sections. In 32 patients the CRM was respected in both exams and 4 patients were considered positive on histopathological findings but negative in MRI. The sensitivity, specificity, positive and negative predictive values for prediction of tumor involvement of CRM were 86%, 80%, 76% and 88%, respectively. Conclusions: MRI gives reliable information on tumor involvement of the CRM in patients with rectal cancer. This may provide accurate identification of an important prognostic risk factor in patients prior to surgical treatment.