Rethinking Surgical Margins in Colorectal Liver Metastases: Vessel-Skeletonized Parenchymal-Sparing Hepatectomy (VESPAH) and Treatment Continuity

Complete (R0) resection remains the primary surgical objective for colorectal liver metastases (CRLM), but margin width cannot be interpreted independently of tumor anatomy, biology, and the amount of functional liver sacrificed to obtain it. This focused narrative review re-examines surgical margins from the perspective of parenchymal preservation and longitudinal multimodal treatment. We distinguish parenchymal R1 exposure (R1par), an undesirable transection-surface event consistently associated with local recurrence in retrospective series, from planned vascular R1 detachment (R1vasc), which has shown more favorable outcomes than R1par in selected retrospective series but remains dependent on careful anatomical selection. Vessel-skeletonized parenchymal-sparing hepatectomy (VESPAH) is presented as one operative model for achieving complete macroscopic clearance while preserving intrahepatic vascular architecture; the evidence for this model is confined to retrospective series and is therefore illustrative and hypothesis-generating rather than confirmatory. We further propose “treatment continuity”—preservation of the physiological and anatomical capacity to receive indicated systemic therapy and repeat local treatment—as a reportable surgical outcome. A four-axis framework integrating technical resectability, functional reserve, tumor biology, and future treatment options is outlined, together with a minimum set of reporting elements for margin phenotype and operational definitions for four candidate measures of treatment continuity. R0 resection should remain the goal, but the quality of hepatectomy for CRLM may be more comprehensively assessed by considering both the margin achieved at the index operation and the treatments that remain feasible thereafter.