Changes in liver resections and associated outcomes over thirty years: a nationwide analysis using a machine learning approach.

BACKGROUND: In contrast to three decades ago, liver resection (LR) is now an increasingly common procedure. This study aims to evaluate changes in the number and indications of liver resections for malignancy over the past 30 years in the Netherlands and the associated survival outcomes. METHOD: All records of surgical resections for liver tumors performed between 1991 and 2020 were extracted from the Dutch nationwide pathology network database. Resection and tumor characteristics were extracted using a machine-learning algorithm. Survival data was acquired through the Dutch Center for Family History. Patient, resection, and tumor characteristics and survival for hepatocellular carcinoma (HCC) and colorectal liver metastases (CRLM) were assessed across decades. RESULTS: Between 1991 and 2020, 19.022 LRs were performed. The annual number of LRs increased from 113 in 1991 to 1.178 in 2020. Liver metastases accounted for 84% of resections, of which 85% were CRLM, while of primary liver tumors 59% were HCC. The annual number of liver resections for colorectal metastases decreased since 2015. Over the decades patients undergoing liver resections were older, with more often multifocal liver tumors and re-resections. Five-year survival rate for CRLM decreased from 44% (1991-2000) to 33% (2011-2020), p < 0.001. Five-year survival rate for HCC patients was stable: 57% (1991-2000), 50% (2001-2010), and 50% (2011-2020), p = 0.681. CONCLUSION: The number of liver resections for malignancies in the Netherlands has sharply increased over the past three decades with expansion of indications. Survival after liver resection for CRLM showed a declining trend, potentially reflecting less stringent patient and tumor characteristics.