Stereotactic Body Radiation Therapy (SBRT) for treatment of adrenal gland metastases from non-small cell lung cancer

Metastatic disease from a non-small cell lung cancer to the adrenal gland is common, and systemic treatment is the most frequent therapeutic option. Nevertheless, in patients suffering from an isolated adrenal metastasis, a survival benefit could be achieved after surgical resection. Stereotactic body radiation treatment (SBRT) increase local tumor control and could be an alternative option. We present our initial institutional experiences with SBRT for adrenal gland metastases. Between July 2002 and September 2009, 18 patients with a non-small cell lung cancer and adrenal metastasis received SBRT. An isolated adrenal metastasis was diagnosed in 13 patients, while 5 patients with multiple metastatic lesions had SBRT due to back pain. Depending on treatment intent and target size, the dose/fraction concept varied from 5 x 4 Gy to 5 x 8 Gy. Dose was given with an isotropic convergent beam technique to a median maximum dose of 132% to the target's central part. The mean clinical (CTV) and planning target volume (PTV) was 89 cmA(3) (5-260 cmA(3)) and 176 cmA(3) (20-422 cmA(3)). A median progression-free survival time (PFS) of 4.2 months was obtained for the entire patient group, with a markedly increased PFS of 12 months in 13 patients suffering from an isolated metastasis of the adrenal gland. After a median follow-up of 21 months, 10 of 13 patients (77%) with isolated adrenal metastasis achieved local control. In these patients, median overall survival (OS) was 23 months. SBRT is a feasible and safe technique for lung cancer patients with adrenal gland metastasis. In patients with an isolated adrenal metastasis median OS of 23 months was excellent and comparable to data after surgical removal, but noninvasive. Acute side effects were mild.