Parenchymal sparing surgery for colorectal liver metastases: The need for a common definition.

BACKGROUND: The definition of parenchymal sparing surgery (PSS) for colorectal liver metastases (CRLM) diverges requiring a clarification of the concept.

METHOD: A consecutive series of patients were treated by PSS for their CRLMs, either by resection or intra-operative ablation (IOA), whenever possible a one-stage surgery and minimal usage of portal vein embolization. Post-operative complications were the primary endpoint with a special focus on post-operative liver failure.

RESULTS: Three hundred and eighty-seven patients underwent a PSS out of which 328 patients received a median of 9 pre-operative cycles of chemotherapy. One hundred and twenty-eight patients had a major resection, combined with IOA in 137 patients and IOA alone in 50 cases. The 5yr-overall survival was 50.3%. There was no difference in post-operative complications between minor and major resections, validating our PSS definition based on the Tumor burden/Healthy liver ratio and not just the retrieved volume.

CONCLUSIONS: PSS is defined as a high ratio of tumoral burden per specimen retrieved while favoring one-stage surgery approach. Our series, using combined resections and IOAs, matches this definition well. Furthermore, complications were correlated neither to chemotherapy nor to liver-induced toxicities, contrary to extended hepatectomies.