In the present study we have evaluated the efficacy and toxicity of repeated stereotactic radiosurgery (SRS) in patients with recurrent/progressive brain metastases. Between March 2006 and October 2014, 43 patients (21 men and 22 women) with 47 lesions received a second course of SRS given in three daily fractions of 7-8 Gy. With a follow-up study of 19 months, the 1- and 2-year survival rates from repeated SRS were 37 and 20%, respectively, and the 1- and 2-year local control rates were 70 and 60%, respectively. Actuarial local control was significantly better for breast and lung metastases as compared with melanoma metastases; specifically, 1-year local control rates were 38% for melanoma, 78% for breast carcinoma and 73% for non-small cell lung cancer (NSCLC) metastases (p = 0.01). The cause of death was progressive systemic disease in 25 patients and progressive brain disease in 11 patients. Stable extracranial disease (p = 0.01) and Karnofsky performance status (KPS; p = 0.03) were predictive of longer survival. Radiologic changes suggestive of brain radionecrosis were observed in 9 (19%) out of 47 lesions, with an actuarial risk of 34% at 12 months. Neurological deficits (RTOG Grade 2 or 3) associated with brain necrosis occurred in 14% of patients. In conclusion, a second course of SRS given in three daily fractions is a feasible treatment for selected patients with recurrent/progressive brain metastases. Further studies are needed to explore the efficacy and safety of different dose-fractionation schedules, especially in patients with melanoma or large metastases.
Keywords: Brain metastases; Brain radionecrosis; Fractionated stereotactic radiotherapy; Reirradiation; Stereotactic radiosurgery.