BACKGROUND: Visceral fat is considered a risk for postoperative complications in colon cancer surgery. However, the association with anastomotic leakage as the most worrisome complication is not clear mainly because of underpowered studies. OBJECTIVE: The purpose of this study was to analyze the effect of visceral fat as a continuous variable on anastomotic leakage in a large cohort of colon cancer resections. DESIGN: This was a retrospective, multicenter cohort study. SETTINGS: This study used data of the Dutch Surgical Colorectal Audit of the years 2011 through 2014 from 8 Dutch teaching hospitals. Visceral fat was assessed on the routine preoperative abdominal CT scan. PATIENTS: A total of 2370 patients underwent colon cancer resection with primary anastomosis. There were 2011 patients operated electively and 359 in an emergency setting. MAIN OUTCOME MEASURES: The effect of visceral fat on anastomotic leakage after multivariable analysis was measured. RESULTS: Visceral fat was associated with anastomotic leakage in the elective colon resection group (n = 2011) but not in emergency colon resections (n = 359). Significant confounding was found for type of resection, BMI, and sex. The association of male sex and BMI as previously reported risk factors for anastomotic leakage was explained by visceral fat. LIMITATIONS: The study was limited by its retrospective character and missing clinical data of known risk factors for anastomotic leakage, like smoking history and certain medication. CONCLUSIONS: The independent association of visceral fat with anastomotic leakage was confined to the elective colon cancer resection group. The previously reported associations of male sex and BMI with anastomotic leakage were explained by visceral fat. Visceral fat–associated comorbidities did not influence anastomotic leakage, suggesting that its effect on colon anastomotic healing is local rather than systemic. Future risk analysis for anastomotic leakage in colon cancer surgery should contain visceral fat values and consider subgroup differences. See Video Abstract at http://links.lww.com/DCR/B396. ADIPOSIDAD VISCERAL Y FUGA ANASTOMÓTICA EN CASOS DE RESECCIÓN DE CÁNCER DE COLON ANTECEDENTES: La acumulación de grasa visceral se considera como un factor de riesgo en caso de complicaciones postoperatorias de cirugía de cáncer de colon. Sin embargo, la asociación con la fuga anastomótica como la complicación más preocupante no está clara principalmente debido a los estudios de bajo impacto disponibles. OBJETIVO: Analizar el efecto de la adiposidad visceral como una variable contínua sobre la fuga anastomótica en una gran cohorte de resecciones de cáncer de colon. DISEÑO: Estudio de cohorte multicéntrico retrospectivo. AJUSTES: Se utilizaron los datos de la Auditoría Colorrectal Quirúrgica Holandesa entre los años 2011 y 2014 en 8 hospitales de enseñanza de los Paises bajos. La grasa visceral fué evaluada por medio de la tomografía computada abdominal preoperatoria de rutina. PACIENTES: Un total de 2370 pacientes fueron sometidos a resección de cáncer de colon con anastomosis primaria. 2011 pacientes fueron operados electivamente y 359 en situación de emergencia. PRINCIPALES MEDIDAS DE RESULTADO: El efecto de la adiposidad visceral en la fuga anastomótica después del análisis multivariable. RESULTADOS: La grasa visceral se asoció con la fuga anastomótica en el grupo de resección electiva de colon (n = 2011) pero no en las resecciones de emergencia (n = 359). Se encontraron factores de confusión significativos para el tipo de resección, el índice de masa corporal y el género. La adiposidad visceral explica la asociación del género masculino y el índice de masa corporal como factores de riesgo reportados previamente en los casos de fugas anastomóticas. LIMITACIONES: Carácter retrospectivo del estudio y la falta de datos clínicos de factores de riesgo conocidos para la fuga anastomótica, como los antecedentes de tabaquismo y el consumo de ciertos medicamentos. CONCLUSIONES: La asociación independiente de la adiposidad visceral con la fuga anastomótica se limitó al grupo de resección electiva por cáncer de colon. Las asociaciones previamente reportadas de género masculino e índice de masa corporal con fuga anastomótica se explicaron por la grasa visceral. Las comorbilidades asociadas a la grasa visceral no influyeron en la fuga anastomótica, lo que sugiere que la cicatrisación anastomótica obedece más a un factor local que a un factor sistémico. Un análisis de riesgos previsibles para fugas anastomóticas en casos de resección de cáncer de colon deben involucrar los valores de la adiposidad visceral y considerar las diferencias entre subgrupos. Consulte Video Resumen en http://links.lww.com/DCR/B396. (Traducción—Dr Xavier Delgadillo)

Background: Muscle and fat influence outcome after colorectal cancer surgery. Little data exist on mortality. Muscle mass (MM) relating to lower mortality is mostly studied in dichotomous approaches as sarcopenia or skeletal muscle index (SMI) but rarely as a continuous variable. For fat, compartments as visceral, subcutaneous, or intramuscular have different metabolic impact but on mortality little is known. Sex dictates muscle and fat mass that also may differ between colon and rectal cancer patients. Objective: To study associations of muscle and fat parameters as continuous variables with mortality in men and women after colon or rectal cancer resection. Design: Retrospective multicenter cohort study Setting: This study used data of the Dutch Surgical Colorectal Audit from 2011 through 2014 from 8 Dutch teaching hospitals. Body composition was assessed on pre-operative CT scans. Patients: 2597 colon and 931 rectal cancer patients Main outcome measures: Associations of muscle and fat measures with 5- year MR in male and female colon and rectal cancer patients. Results: Negative associations of MM and SMI and positive associations of muscle fat (MF) and sarcopenia with mortality were found only in male patients. The effect of MM and sarcopenia was found in both colon and rectal patients whereas SMI had no effect in rectal patients. Muscle fat associated with higher mortality only in male colon patients. The only effect of visceral fat was seen in male rectal cancer patients associating with lower mortality. Limitations: The retrospective nature of the study Conclusion: The male predominance and differences between colon and rectal cancer patients for associations of muscle and fat parameters with colorectal cancer mortality stress the importance of separating males from females and colon from rectal cancer patients in the analysis of body composition effects on mortality.