OBJECTIVES:This study sought to determine the clinical and pathological factors associated with perioperative morbidity, mortality and oncological outcomes after multivisceral en bloc resection in patients with colorectal cancer.METHODS:Between January 2009 and February 2014, 105 patients with primary colorectal cancer selected for multivisceral resection were identified from a prospective database. Clinical and pathological factors, perioperative morbidity and mortality and outcomes were obtained from medical records. Estimated local recurrence and overall survival were compared using the log-rank method, and Cox regression analysis was used to determine the independence of the studied parameters. ClinicalTrials.gov: NCT02859155.RESULTS:The median age of the patients was 60 (range 23-86) years, 66.7% were female, 80% of tumors were located in the rectum, 11.4% had stage-IV disease, and 54.3% received neoadjuvant chemoradiotherapy. The organs most frequently resected were ovaries and annexes (37%). Additionally, 30.5% of patients received abdominoperineal resection. Invasion of other organs was confirmed histologically in 53.5% of patients, and R0 resection was obtained in 72% of patients. The overall morbidity rate of patients in this study was 37.1%. Ureter resection and intraoperative blood transfusion were independently associated with an increased number of complications. The 30-day postoperative mortality rate was 1.9%. After 27 (range 5-57) months of follow-up, the mortality and local recurrence rates were 23% and 15%, respectively. Positive margins were associated with a higher recurrence rate. Positive margins, lymph node involvement, stage III/IV disease, and stage IV disease alone were associated with lower overall survival rates. On multivariate analysis, the only factor associated with reduced survival was lymph node involvement.CONCLUSIONS:Multivisceral en bloc resection for primary colorectal cancer can be performed with acceptable rates of morbidity and mortality and may lead to favorable oncological outcomes.