Stereotactic or conformal radiotherapy for adrenal metastases: Patient characteristics and outcomes in a multicenter analysis. Issue 2 (25th March 2021) - Buergy, Daniel
Abstract: To report outcome (freedom from local progression [FFLP], overall survival [OS] and toxicity) after stereotactic, palliative or highly conformal fractionated (>12) radiotherapy (SBRT, Pall‐RT, 3DCRT/IMRT) for adrenal metastases in a retrospective multicenter cohort within the framework of the German Society for Radiation Oncology (DEGRO). Adrenal metastases treated with SBRT (≤12 fractions, biologically effective dose [BED10] ≥ 50 Gy), 3DCRT/IMRT (>12 fractions, BED10 ≥ 50 Gy) or Pall‐RT (BED10 < 50 Gy) were eligible for this analysis. In addition to unadjusted FFLP (Kaplan‐Meier/log‐rank), we calculated the competing‐risk‐adjusted local recurrence rate (CRA‐LRR). Three hundred twenty‐six patients with 366 metastases were included by 21 centers (median follow‐up: 11.7 months). Treatment was SBRT, 3DCRT/IMRT and Pall‐RT in 260, 27 and 79 cases, respectively. Most frequent primary tumors were non‐small‐cell lung cancer (NSCLC; 52.5%), SCLC (16.3%) and melanoma (6.7%). Unadjusted FFLP was higher after SBRT vs Pall‐RT ( P = .026) while numerical differences in CRA‐LRR between groups did not reach statistical significance (1‐year CRA‐LRR: 13.8%, 17.4% and 27.7%). OS was longer after SBRT vs other groups ( P < .05) and increased in patients with locally controlled metastases in a landmark analysis ( P < .0001). Toxicity was mostly mild; notably, four cases of adrenal insufficiency occurred, two of which were likely caused by immunotherapy or tumor progression. Radiotherapy for adrenal metastases was associated with a mild toxicity profile in all groups and a favorable 1‐year CRA‐LRR after SBRT or 3DCRT/IMRT. One‐year FFLP was associated with longer OS. Dose‐response analyses for the dataset are underway. Abstract : What's new? When added to systemic therapy, does local treatment reduce recurrence or overall survival (OS) for patients with limited metastases? In this study, the authors found that, in patients with adrenal metastases, both stereotactic body radiotherapy (SBRT) and highly conformal, intensity‐modulated radiotherapy (3DCRT/IMRT) were associated with a decreased local recurrence rate and a mild toxicity profile. Local control at 12 months was, in turn, associated with increased OS.