Volume-outcome relationship in anatomical and non-anatomical liver resections: a rapid systematic review

BACKGROUND: Despite considerable advancements in recent decades, mortality and complications following liver resection remain high. The volume-outcome relationship has been the subject of extensive research and offers relevant potential for improvement of surgical outcomes. This review aims to examine the impact of hospital and surgeon volume on patient-relevant outcomes in liver resections and synthesize the available evidence. METHODS: A rapid systematic literature review was conducted, searching CENTRAL, Embase, PubMed, and study registries for articles published from 2000 to 2023. Eligible studies investigated the association between hospital or surgeon volume and patient-relevant outcomes in anatomical and non-anatomical liver resections. Study quality was assessed using the ISPOR and ROBINS-E checklists and reported alongside the results. The review protocol registered with PROSPERO (CRD42023398566). RESULTS: The search yielded 3287 records, of which 38 publications met the inclusion criteria. All included studies were retrospective observational studies. A higher surgical volume was associated with improved patient-relevant outcomes, such as reduced mortality following both anatomical and non-anatomical liver resections and lower rates of postoperative complications. However, the results indicate that the impact of hospital or surgeon volume is limited and likely depends on the respective outcome parameter. A considerable gap remains with respect to long-term outcomes and quality of life, and studies investigating surgeon volume are scarce. CONCLUSION: The findings provide evidence supporting a positive association between higher hospital volume and improved patient-relevant outcomes in liver resection. However, surgeon volume remains underexplored and the evidence from subgroups indicates that the impact of hospital or surgeon volume likely depends on study quality, procedure type, volume thresholds, and respective outcome parameters. Patient care could benefit from further research on long-term outcomes as well as quality of life, for which the current evidence is scarce.