Comparative outcomes of radiotherapy and interventional therapy for adrenal oligometastases: A multicenter retrospective study.

Abstract

1 Background: Adrenal oligometastatic disease (OMD) represents an intermediate state between localized and systemic malignancy, with adrenal involvement in 10–25% of carcinoma cases. Aggressive local therapy may achieve durable remission. While systemic therapy remains essential, local control often requires surgery, interventional therapy, or radiotherapy. Adrenalectomy offers survival benefit but carries morbidity; Radiotherapy and interventional therapy provide > 80% local control and > 50% 3-year OS with minimal toxicity. However, direct comparisons remain limited. This study compares radiotherapy and interventional therapy for adrenal OMD, assessing LPFS (Local Progression-Free Survival), OS (Overall Survival), and toxicity across tumor types and disease settings to define optimal management. Methods: This multicenter retrospective study compared radiotherapy and interventional therapy for adrenal oligometastases (≤5 lesions ≤3 organs) in 118 patients (2008–2024). Primary endpoint was OS; secondary LPFS. IPTW-adjusted Cox analysis showed balanced covariates (SMD < 0.10). Radiotherapy delivered median 40 Gy (BED10 = 60 Gy); interventional therapy median 1.17 h, 3-day stay. Outcomes and toxicity were compared using weighted models. Results: Between 2008–2024, 245 patients with adrenal metastases were analyzed (127 radiotherapy, 118 intervention). Baseline features were balanced after IPTW (SMD < 0.1). At 20.6 mo mean follow-up, local recurrence was 17.3% vs 22.0%; deaths 44.9% vs 70.3%. Unadjusted LPFS HR 1.29 (0.92–1.81) and OS HR 1.39 (0.96–2.00) showed no significant difference; adjusted LPFS HR 1.29 (0.91–1.84) and OS HR 1.30 (0.89–1.89) confirmed equivalence. Subgroup analyses revealed poorer outcomes with intervention among females (HR 2.29, P = 0.03) and lung primaries (interaction P = 0.03), while synchronous disease favored intervention (HR 1.99, P = 0.05). Multivariate Cox identified lung primaries (HR 2.68, P = 0.0003) and lesion > 42 mm (HR 2.25, P = 0.0009) as mortality predictors. Bilateral and medium lesions predicted LPFS failure (HR 2.80, P = 0.005). Toxicity was acceptable: radiotherapy led to more mild respiratory/hematologic events (6.9%, 3.5%), intervention to pain (10.2%), pneumothorax (3.7%), renal injury (5.7%). No procedure-related deaths occurred. Conclusions: In 245 patients with adrenal metastases, adjusted comparisons showed radiotherapy and interventional therapy had similar efficacy. Radiotherapy showed nonsignificant OS and LPFS benefits. Subgroups (female, synchronous, 42–80 mm lesions) showed distinct responses. Lung primaries and tumors > 42 mm predicted poor OS; bilateral or intermediate lesions impaired control. Toxicities differed but remained tolerable.