Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) is an extensive procedure with considerable morbidity. Since only few hospitals perform CRS + HIPEC, this might lead to confounded outcomes between hospitals when audited. This study aims to compare outcomes between peritoneally metastasized (PM) colon cancer patients treated with CRS + HIPEC and patients undergoing conventional colon surgery. Furthermore, the impact of CRS + HIPEC on the risk of postoperative complications will be assessed, probably leading to better insight into how to report on postoperative outcomes in this distinct group of patients undergoing extensive colon surgery.All patients with primary colon cancer who underwent segmental colon resection in a tertiary referral hospital between 2011 and 2014 were included in this prospective cohort study. Outcome after surgery was compared between patients who underwent additional CRS + HIPEC treatment or conventional surgery.Consequently, 371 patients underwent surgery, of which 43 (12%) underwent CRS + HIPEC. These patients were younger and healthier than patients undergoing conventional surgery. Tumor characteristics were less favorable and surgery was more extensive in CRS + HIPEC patients. The morbidity rate was also higher in CRS + HIPEC patients (70% vs 41%; P < 0.001). CRS + HIPEC was an independent predictor of postoperative complications (odds ratio 6.4), but was not associated with more severe postoperative complications or higher treatment-related mortality.Although patients with colonic PM undergoing CRS + HIPEC treatment were younger and healthier, the postoperative outcome was worse. This is most probably due to less favorable tumor characteristics and more extensive surgery. Nevertheless, CRS + HIPEC treatment was not associated with severe complications or increased treatment-related mortality. These results stress the need for adequate case-mix correction in colorectal surgery audits.