Stereotactic Radiosurgery in the Treatment of Recurrent CNS Lymphoma

Background Central nervous system lymphoma (CNSL) is typically treated with chemotherapy and external beam radiation therapy (EBRT). Optimal management of recurrent CNSL is poorly defined. Objective We aim to determine the effectiveness of stereotactic radiosurgery in the treatment of recurrent CNSL. Methods We performed a retrospective analysis of patients having stereotactic radiosurgery (SRS) for recurrent intracranial CNSL between 1999 and 2011. Results Fourteen patients (20 tumors) underwent SRS. The median patient age was 71 years (range, 18-82 years). Seven patients (50%) had primary CNSL. All had received prior chemotherapy, and nine patients (64%) had undergone prior whole brain radiotherapy (WBRT) with a median dose of 40 Gy in 25 fractions. The median preoperative Karnofsky Performance Score was 80. The median tumor volume was 6.7 cm³ (range, 0.5-37.7); the median margin dose was 15.5 Gy (range, 10-18). Eleven patients (79%) had tumor regression (n = 11) shown on MRI after SRS. The median overall survival after SRS was 9.5 months. No patient had a major radiation-related complication. Conclusion Stereotactic radiosurgery for patients with recurrent CNSL is well tolerated and has a high rate of radiographic response. A marginal dose of 15.5 Gy or greater, a Karnofsky score of 80 or greater, and the absence of pre-SRS WBRT were associated with significantly longer overall survival. Stereotactic radiosurgery may be beneficial as an initial salvage therapy in the treatment of recurrent CNSL for properly selected patients.