Radiotherapy for Adrenal Metastases from Hepatocellular Carcinoma: A 20-Year Bi-Institutional Experience

Background: To evaluate tumor response, local control (LC), survival, and toxicity after radiotherapy for adrenal metastases from hepatocellular carcinoma (HCC), we conducted a retrospective, bi-institutional study spanning two decades. Methods: Twenty patients received radiotherapy for adrenal metastases (2005–2025). Techniques included three-dimensional conformal radiotherapy, intensity-modulated radiotherapy, stereotactic body radiotherapy, and MR-guided radiotherapy. Tumor response was assessed using Response Evaluation Criteria in Solid Tumors version 1.1. LC, overall survival (OS), and progression-free survival (PFS) were estimated using Kaplan–Meier; the association between biologically effective dose (BED10) and local recurrence was assessed using Fisher’s exact test. Results: The objective response rate was 55.0%, and the disease control rate was 95.0%. The 6- and 12-month adrenal LC rates were 94.4% and 87.2%; local recurrence occurred in three patients (15.0%). No local recurrence was observed at BED10 ≥ 75 Gy (0/8) versus 25.0% (3/12) at BED10 < 75 Gy. However, this difference did not reach statistical significance (p = 0.242, Fisher’s exact test) and should be interpreted as exploratory and hypothesis-generating given the limited sample size. Median OS was 13.4 months, and median PFS was 6.3 months. Systemic progression was the predominant failure pattern. No grade ≥3 radiotherapy-related toxicity was observed. Conclusions: Radiotherapy achieved favorable LC with acceptable toxicity across a 20-year bi-institutional experience, supporting its role as an effective local treatment modality for adrenal metastases from HCC.