Waiting time and explant pathology in transplant recipients with hepatocellular carcinoma: a novel study using national data.

Risk factors for hepatocellular carcinoma (HCC) recurrence after liver transplantation have been well described. It has been surmised that longer time on the waitlist may select for tumors with a lower-risk of recurrence posttransplant, as patients with unfavorable tumor characteristics would be delisted due to tumor progression. Utilizing national explant pathology records from transplant recipients waitlisted with T2 HCC exception points, this study explored the correlation between waiting time and the development of pathologic HCC features associated with increased risk of tumor recurrence. Of 1976 explant pathology reports submitted nationally between April 8, 2012 and June 30, 2013, 1453 (73.5%) were from recipients with automatic T2 HCC exception points. There was no association between pretransplant waiting time and the proportion of HCC explants with either: (i) a poorly differentiated tumor; (ii) macrovascular invasion; (iii) HCC beyond Milan or University of California San Francisco criteria; (iv) HCC beyond the "up-to-seven" criteria; or (v) extra-hepatic or lymph node involvement. Though there was a statistically significant increase in microvascular invasion in recipients with pretransplant waiting 6-12 months, this association was not seen when adjusted for United Network for Organ Sharing region. These findings suggest that waiting time alone may not select for tumors with more favorable characteristics. © Copyright 2014 The American Society of Transplantation and the American Society of Transplant Surgeons.