Omission of or Poor Response to Preoperative Chemoradiotherapy Impacts Radial Margin Positivity Rates in Locally Advanced Rectal Cancer.

BACKGROUND In the setting of multidisciplinary standardized care of locally advanced rectal cancer, preoperative chemoradiotherapy and total mesorectal excision have become the mainstay treatment. OBJECTIVE This study aimed to evaluate whether the lack of preoperative chemoradiotherapy or poor response to it is associated with higher radial margin disease involvement in patients with locally advanced rectal cancer. DESIGN This is a retrospective cohort study using a publicly available database. SETTING Data were collected from the proctectomy-targeted National Surgical Quality Improvement Project file from 2016 to 2017. PATIENTS A total of 1161 patients were analyzed. They were categorized into 3 groups: patients who did not receive any preoperative chemoradiotherapy (28.6%), patients who received and responded to preoperative chemoradiotherapy (41.2%), and patients who received but did not respond to preoperative chemoradiotherapy (30.2%). MAIN OUTCOME MEASURES Response to treatment was determined by using the American Joint Committee on Cancer pretreatment and final pathological staging. Circumferential radial margin was extracted from the targeted proctectomy file. RESULTS Disease-involved positive circumferential radial margin was found in 86 (7.4%) cases. Positive radial margin was noted in 11 of 479 patients (2.3%) who underwent preoperative chemoradiotherapy and responded to treatment, 30 of 350 patients (8.6%) who did not respond or had a poor response to preoperative chemoradiotherapy, and 45 of 332 patients (13.6%) who did not receive preoperative chemoradiotherapy (p < 0.001). Regression analysis demonstrated that patients who do not receive preoperative chemoradiotherapy or have poor response to it have 6.6 and 4 times higher chances of having a positive radial margin. LIMITATIONS There is a risk of selection bias, unidentified confounders, and missing data despite the use of a nationwide cohort. CONCLUSIONS Omission of indicated preoperative chemoradiotherapy or poor response to it is associated with increased risk of radial margin positivity. More efforts are needed for standardized rectal cancer care with the appropriate use of preoperative chemoradiotherapy. See Video Abstract at http://links.lww.com/DCR/B467. LA OMISIN O LA ESCASA RESPUESTA A QUIMIORADIOTERAPIA PREOPERATORIA, AFECTA LAS TASAS DE POSITIVIDAD DEL MARGEN RADIAL, EN EL CNCER RECTAL LOCALMENTE AVANZADO ANTECEDENTES:En el contexto de la atencion multidisciplinaria estandarizada del cancer rectal localmente avanzado, la quimioradioterapia preoperatoria y la escision mesorrectal total, se han convertido en el tratamiento principal.OBJETIVO:Evaluar si la omision de quimioradioterapia preoperatoria o la escasa respuesta, se asocia con mayor enfermedad del margen radial, en pacientes con cancer rectal localmente avanzado.DISENO:Estudio de cohorte retrospectivo utilizando una base de datos disponible publicamente.AJUSTE:Se recopilaron datos del archivo del Proyecto Nacional de Mejora de la Calidad Quirurgica dirigido a la proctectomia de 2016-2017.PACIENTES:Se analizaron un total de 1161 pacientes. Clasificados en tres grupos: pacientes que no recibieron quimioradioterapia preoperatoria (28,6%), pacientes que recibieron y respondieron a quimioradioterapia preoperatoria (41,2%) y pacientes que recibieron pero no respondieron a la quimioradioterapia preoperatoria (30,2%).PRINCIPALES MEDIDAS DE RESULTADO:La respuesta al tratamiento se determino utilizando el pre tratamiento y la estatificacion patologica final, del American Joint Committee on Cancer. El margen radial circunferencial se extrajo del archivo de proctectomia dirigida.RESULTADOS:Se encontro enfermedad que abarcaba el margen radial circunferencial +, en el 86 (7,4%) casos. Se observo el margen radial +, en 11 de 479 pacientes (2,3%) que se sometieron a quimioradioterapia preoperatoria y respondieron al tratamiento, 30 de 350 pacientes (8,6%) que no respondieron o tuvieron una mala respuesta con quimioradioterapia preoperatoria y en 45 de 332 pacientes (13,6%) que no recibieron quimioradioterapia preoperatoria (p <0,001). El analisis de regresion demostro que los pacientes que no reciben quimioradioterapia preoperatoria o que tienen escasa respuesta, presentan respectivamente, 6,6 y 4 veces mas probabilidades de tener un margen radial +.LIMITACIONES:Existe el riesgo de sesgo de seleccion, factores de confusion no identificados y datos faltantes a pesar del uso de una cohorte nacional.CONCLUSIONES:La omision de la quimioradioterapia preoperatoria indicada o la escasa respuesta, se asocian a un mayor riesgo de positividad del margen radial. Se necesitan mayores esfuerzos en la atencion estandarizada del cancer rectal, con el uso adecuado de quimioradioterapia preoperatoria. Consulte Video Resumen en http://links.lww.com/DCR/B467.