Abstract 704: Primary versus delayed surgery in fibrolamellar carcinoma

Abstract Background: Fibrolamellar carcinoma (FLC) is a rare, primary liver cancer of young adults without liver disease, distinct from hepatocellular carcinoma (HCC), usually presenting as advanced stage. FLC has been thought of as a "surgical disease." Because of a lack of data, and a legacy of FLC being mislabeled as “fibrolamellar HCC, ” recommendations have been similar to HCC with upfront surgery considered for all new diagnosis and systemic therapy reserved for those deemed inoperable. Our foundation has assembled the largest collection of FLC cases to date. We reviewed surgery data in FLC stratified by stage and systemic therapy. Methods: We report 216 cases of FLC from our own database and 24 from the medical literature that included: Information about demographics, surgery, systemic therapy, staging, time to relapse and overall survival. We defined “localized” as confined to the liver (AJCC stage 1), “regional” as regional lymph node involvement at surgery (AJCC stage 2 and 3), and “metastatic” (AJCC stage 4) as distant metastasis. Results: Of 155 patients with initial surgery, 44 (28%) had adjuvant systemic therapy and 85 ‘unresectable’ patients had neo-adjuvant therapy converting 31 patients to have delayed surgery (36%). Relapses were nearly universal (89% at 5 years). There was 100% 10-year survival for localized disease, but frequent relapses nonetheless. Adjuvant therapy gave regional patients a survival advantage. Neo-adjuvant therapy benefited metastatic patients as well as providing as significant delay in time to relapse. Benefit to 54 metastatic patients who had neoadjuvant therapy but no surgery was also seen. [Table1] Conclusion: Primary surgery for localized FLC offers excellent long-term control, but regional and metastatic FLC should be considered systemic diseases and systemic therapy before surgery should be considered before committing to initial resection. Neoadjuvant therapy can covert unresectable patients to resectable, and adjuvant therapy appears to benefit all non-localized patients. Citation Format: Paul M. Kent, Tomoaki Kato, Abhinar Humar, Oliver Fisher, Matthew Dixon, Christopher Seder, Tom Stockwell. Primary versus delayed surgery in fibrolamellar carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 704.