Combined retroperitoneal resection with cytoreductive surgery and heated intraperitoneal chemotherapy for metastatic colorectal cancer with retroperitoneal and peritoneal metastases

Introduction Colorectal peritoneal metastases (CRPM) and retroperitoneal lymphatic metastases (RLM) are each considered poor prognostic indicators in colorectal cancer (CRC). Current data suggests that surgery for each including cytoreductive surgery and heated intraperitoneal chemotherapy (CRS/HIPEC) for CRPM and retroperitoneal resection (RR) for RLM may improve survival. Given the poor prognosis of each finding individually, each condition is generally considered a contraindication to the other. We describe the first series of combined RR and CRS/HIPEC. Materials and methods Retrospective analysis of a prospectively maintained tertiary institution database comparing perioperative and oncological outcomes of combined RR + CRS/HIPEC to CRS/HIPEC only in CRC. Results Included 238 CRS/HIPEC and divided to 17 with RR + CRS/HIPEC and 221 with CRS/HIPEC only. Demographic/perioperative characteristics were similar including tumor characteristics and peritoneal cancer index. Longer operative times observed in RR + CRS/HIPEC cohort (5 versus 4 h, p  = 0.024). Complications were similar except more postoperative bleeding events and deep vein thrombosis in the RR + CRS/HIPEC cohort (24 % versus 5.0 %, p  = 0.024 and 12 % versus 2.3 %, p  = 0.026, respectively). This did not translate to longer length of stay, reoperations, or major complications. Median disease free survival was shorter in the RR + CRS/HIPEC cohort (7.3 versus 11.3 months, p  = 0.032), but similar overall survival observed (29.5 versus 43.9 months, p  = 0.34). Less retroperitoneal recurrences occurred after regional lymphadenectomy (12 %) compared to mass only resection (44 %). Conclusion Our study demonstrates the safety and oncological efficacy of RR + CRS/HIPEC. We believe that RR + CRS/HIPEC in highly selected patients is a suitable option and hope this leads to larger multi-institutional studies to corroborate these findings.