Hypofractionated Radiotherapy for 35 Patients with Adrenal Metastases: A Single-Institution Experience

To investigate the clinical outcomes of hypofractionated radiotherapy for adrenal metastases.

We retrospectively reviewed patients diagnosed with adrenal metastases and treated with hypofractionated radiotherapy, who did not receive adrenalectomy or have disease progression after chemotherapy, from 2007 to 2019. The Kaplan-Meier method was used to estimate local control rate (LCR), progression-free survival (PFS), and overall survival (OS). Univariate analysis was performed using Log rank test.

Thirty-five patients with 42 lesions were enrolled, and the lung was the most common primary site (80.0%). The median follow-up time was 46.4 months. The median volume of GTV and PTV was 23.2 cm³ (range: 3.5-97.8 cm³) and 38.3 cm³ (range: 10.2-135.6 cm³), respectively. The main dose regimens were 60 Gy delivered in 4-15 fractions, with the median dose of PTV being 60 Gy (range: 40-66.3 Gy) and the biologically effective dose (BED) being 84 Gy (range: 56-110 Gy). The 1-year and 2-year LCR, OS, and PFS were 92.7% and 88.1%, 76.9% and 45.4%, and 25.1% and 14.4%, respectively. Univariate analysis showed that chemotherapy, disease-free interval from primary disease diagnosis to adrenal metastases diagnosis, and age were significant factors for LCR, OS, and PFS, respectively (p=0.017, 0.049, and 0.004, respectively). No more than grade III toxicities were observed.

As a non-invasive approach, hypofractionated radiotherapy is safe and effective for metastatic adrenal lesions, without serious complications.