Stereotactic body radiotherapy for adrenal metastases from lung cancer

Purpose The adrenal glands are common sites of metastatic disease in lung cancer and can be highly symptomatic. Current treatment approaches for adrenal oligometastases, including surgical resection and chemoembolization, are invasive and can be associated with considerable morbidity. More recently, stereotactic body radiotherapy (SBRT) has shown promising tumor control rates in primary lung cancer and oligometastases of various sites, but relatively less data exist on the efficacy of SBRT for adrenal metastases. The purpose of this study is to assess tumor regression pattern, local control, overall survival, pain relief, and treatment morbidity in patients treated with SBRT for adrenal metastases from lung cancer. Methods and materials Eleven lesions were treated with SBRT in nine patients with lung cancer and followed with post-therapy clinical exams and computed tomography. Response Evaluation Criteria in Solid Tumors (RECIST)-based tumor response was assessed and volumetric tumor measurements were obtained by serial three-dimensional contouring. Symptomatic control, overall survival, and radiation therapyassociated side effects were assessed at follow-up visits. Mean post-therapy follow-up was 7.3 months. Results The prescribed dose ranged from 20.0 to 37.5 Gy in five fractions (mean, 24.9 +/- 7.6 Gy), corresponding to a BED10 of 28.0 to 65.6 (mean, 41.6 +/- 11.6) Gy. Overall RECIST-based response rate was 67%; 1-year and 2-year local control was 44%; and 1-year and 2-year overall survival were 52% and 13%, respectively. Volumetric response was much more rapid in small cell than in non-small cell carcinomas (slope, -31.0% vs. -5.9%/ month, respectively, p00.06). Patients with metachronous lesions had longer survival (1 year, 60%; 2 year, 20%) than patients with synchronous lesions (1 year, 38%; 2 year, 0%). No early or late grade = 3 adverse effects occurred. Conclusion SBRT is a useful non-invasive treatment option for adrenal metastases from lung cancer, providing good local control with minimal morbidity. Small cell carcinoma lesions show rapid response that may require adaptive re-planning.