Facility Volume Thresholds for Optimization of Short- and Long-Term Outcomes in Patients Undergoing Hepatectomy for Primary Liver Tumors.

Background: Volume-outcome relationships have been described for a variety of surgical procedures. We aimed to define the facility volume threshold at which postoperative mortality after hepatectomy was optimal.

Methods: We determined volume percentiles for institutions performing hepatectomy for any primary liver tumor within the National Cancer Database (2004-2017). Marginal structural logistic regression defined the volume percentile (Vmin) at which the odds of 90-day mortality were optimally reduced in patients with hepatocellular carcinoma (HCC) or intrahepatic cholangiocarcinoma (ICC). Short-term postoperative and survival outcomes were compared between patients treated at facilities above and below Vmin.

Results: Thresholds for the 10/25/50/75/90 percentiles were 2/7/26/46/59 hepatectomies/year. A total of 17,833 patients underwent resection of HCC or ICC. The 90-day postoperative mortality was optimized at the 75 percentile for all hepatectomies (IP-weighted OR = 0.67, 95% CI = 0.52-0.87) and major hepatectomy (IP-weighted OR = 0.62, 95% CI = 0.49-0.80). Seven of 446 facilities met the Vmin threshold. The odds of 30-day mortality were also reduced for all hepatectomies (IP-weighted OR = 0.55, 95% CI = 0.42-0.73) and major hepatectomy (IP-weighted OR = 0.58, 95% CI = 0.41-0.75). There were no differences in length of stay or 30-day readmission rate. Patients with HCC or ICC treated at facilities ≥ 10 percentile had an associated improvement in overall survival.

Conclusions: Resection of HCC and ICC is performed at a large number of facilities. Postoperative mortality is optimally reduced at facilities performing at least 46 liver operations annually. Regionalization of surgical care among patients with primary liver malignancies to high-volume centers may result in improved outcomes.