Real-world correlation of RFS and OS in early-stage hepatocellular carcinoma treated with curative intent: A retrospective analysis of SEER-Medicare data.

Abstract

451 Background: Curative intent therapy with resection or ablation for early-stage HCC is associated with high incidence of recurrence. Effective adjuvant therapy is needed to improve outcomes. While OS is the preferred endpoint for demonstrating efficacy of new adjuvant therapies, recurrence-free survival (RFS) may better reflect the benefits associated with adjuvant therapy due to being independent of subsequent therapies upon recurrence. Additionally, RFS may provide insights into patient (pt) outcomes while OS data are immature. We assessed the correlation between OS and RFS in pts with early-stage HCC after treatment with curative intent. Methods: This study used the SEER-Medicare database (2007–2017). RFS was defined as time from curative intent therapy, by local ablation or surgical resection, until death or disease recurrence (first of: new HCC treatment, liver transplant, metastatic disease). OS was defined as time from curative intent therapy until death. Kaplan-Meier analyses were used, censoring on end of Medicare Parts A/B/D continuous eligibility or end of data availability. RFS/OS were summarized overall and by type of prior local therapy and risk of recurrence. Pts with a solitary tumor with histologic grade 3 or 4, solitary tumor >3cm, or multiple tumors were classified as high to very high risk. Pts with a solitary tumor not histologic grade 3 or 4 or a solitary tumor ≤3 cm were classified as low to intermediate risk. Correlation between RFS and OS was assessed using the Kendall’s τ rank correlation. Results: 611 HCC pts met the inclusion criteria (mean follow-up 3.3 years; mean age 73.3 years). Average (median) primary tumor size at diagnosis was 4.8 (4) cm. 91.6% of pts had a solitary tumor at diagnosis. 66.1% of pts experienced death or recurrence (Table). Median [IQR] OS and RFS post-curative intent therapy were 4.6 [1.8, NR] and 1.8 [0.8, 6.3] years, respectively. OS and RFS were poorer for those in the ablation (median OS 3.2 years; RFS 1.2 years) and high to very high risk of recurrence group (median OS 4.3 years; RFS 1.4 years). Kendall’s τ rank correlation model in the overall group demonstrated a statistically significant positive correlation between RFS and OS (τ = 0.66; 95% CI: 0.60–0.70; P < 0.001). Conclusions: Based on real-world data, a significant positive correlation between RFS and OS supports RFS as an efficacy marker and appropriate endpoint for pts in adjuvant HCC setting when OS data are immature. [Table: see text]