Conditional disease-free survival after liver resection for HCC

Abstract

Background: A high recurrence rate after resection of hepatocellular carcinoma (HCC) is one of the most debated issues in literature.Conditional survival is defined as the probability of surviving for another “Y” years, given that the person has already survived “X” years and is derived from the concept of conditional probability in biostatistics. The literature about conditional disease-free survival (CDFS) in patients with HCC after curative resection is very limited.The study aim was to investigate the long-term change in tumor recurrence risk in disease-free patients (DFS) after hepatic resection for HCC. Recurrence probability over time was estimated by CDFS analysis. Methods: 477 consecutive patients that underwent liver resection surgery with curative intent for HCC at the General and Hepatobiliary Surgery Department of the University of Verona from May 1989 to December 2020 were retrospectively analyzed.Long-term endpoints were the DFS, i.e., the time elapsed between the intervention and the first relapse (or the last follow up in case of no relapse) and calculation of the conditional disease-free survival (CDFS) specified as the 1, 2 and 3-year CDFS, which represents the probability of remaining disease-free for an additional 1, 2 and 3 years. Besides, prognostic factors associated with disease-free survival were identified and the change in their impact over time was analyzed. Results: Disease-free survival was 68.2%, 53.6%, 41.6% at 1, 2 and 3 years. Conditional disease-free survival rates of the entire study population based on the time already lived after surgical resection have been evaluated.There were significant differences between DFS and CDFS. The disease-free survival at 5 years was 27.0%, but patients who had already 3 years of disease-free after surgery, had a 64.9% chance of having a further 2 years of disease-free survival. Prognostic factors for DFS and their changes over time have been evaluated. We found that multinodular HCC, HCV, macrovascular invasion and high AFP were significantly related to DFS in baseline analysis, but these factors were no longer related with DFS after X months. Cirrhosis remains the only risk factor for recurrence with statistical significance over the 3 years of DFS. Conclusions: Conditional disease-free survival analysis shows that the prognosis varies over time and is an important tool that can provide more accurate and dynamic prognostic information useful to guide follow-up strategies.