Subclassification of Multivisceral Resections for T4b Colon Cancer with Relevance for Postoperative Complications and Oncological Risks.

BACKGROUND: Multivisceral resection for T4b colon cancer constitutes a heterogeneous group of surgical procedures. The purpose of this study was to explore clinically distinct categories of multivisceral resection, with subsequent correlation to postoperative complications and oncological outcomes. METHODS: In this multicenter cohort study, all consecutive patients without metastases who underwent multivisceral resection for pT4bN0-2M0 colon cancer between 2000 and 2014 were included. Multivisceral resection was divided into four categories: (i) gastrointestinal (including the stomach), (ii) urologic ((partial) bladder and ureter), (iii) solid organ (spleen, kidney, liver, pancreas, and uterus), and (iv) abdominal wall/omentum/ovaries. The primary outcome was surgical complications and secondary outcomes were 5-year intra-abdominal recurrence, disease-free survival, and overall survival. RESULTS: In total, 130 patients who underwent curative intent resection of pT4 colon cancer were included. Patients who underwent multivisceral resection within multiple categories were assigned to one of the categories based on hierarchy of clinical impact after exploratory analysis. For the primary endpoint, 55 patients were assigned to gastrointestinal, 14 to urologic, 14 to solid organ, and 47 to abdominal wall/omentum/ovaries multivisceral resection. Gastrointestinal multivisceral resection was independently associated with surgical complications (HR 3.9, 95% CI 1.4-10.6). Abdominal wall/omentum/ovaries multivisceral resection was significantly related with intra-abdominal recurrence (HR 7.8, 95% CI 1.0-57.8). The 5-year disease-free survival and overall survival showed no significant differences per multivisceral resection category. CONCLUSIONS: Multivisceral resections for T4b colon cancer are heterogeneous procedures considering risk profiles. The proposed multivisceral resection subclassification needs validation, but might improve comparability between studies and hospitals (auditing).