Utility of graded prognostic assessment in evaluation of patients with brainstem metastases treated with radiosurgery.

OBJECTIVES

Prospective data regarding the safety and efficacy of stereotactic radiosurgery (SRS) for patients with metastatic disease involving the brainstem are lacking. The aim of this study was to assess the efficacy and toxicity of SRS for patients with brainstem metastases treated at our institution.

PATIENTS AND METHODS

From September 2007 to October 2015, patients treated with SRS for brain metastases were prospectively entered into an institutional database. Forty eight patients with 51 lesions involving the brainstem with clinical follow-up were identified. Local control (LC), elsewhere brain failure (EBF) and overall survival (OS) were assessed from the date of radiosurgery using the Kaplan-Meier method. Univariate and multivariate analyses of factors related to OS were performed using a Cox proportional hazards model.

RESULTS

Median clinical follow-up was 4.8 months. Median patient age was 62 (range: 28-87); non-small cell lung and breast cancer were the most common primaries at 54% and 21% respectively. Median brainstem lesion volume was 0.12cm(3) (range: 0.01-3.67cm(3)). Whole brain radiotherapy was previously utilized in 19 patients (40%). The median OS was 7.6 months and the 12 month LC rate was 89%. Only 2 patients (4%) experienced grade 3 motor toxicity secondary to SRS. 11 of the 16 patients (69%) initially presenting with symptoms related to brainstem metastases had symptom improvement or resolution following SRS. On multivariate analysis, graded prognostic assessment (GPA) score>2 was predictive of improved survival (p<0.01) while prior chemotherapy use predicted decreased survival (p=0.049).

CONCLUSIONS

SRS is associated with high LC rates and low toxicity for brainstem metastases. Improved OS was seen for patients with GPA score>2. GPA appears to be a useful tool for assessing prognosis in patients with brainstem metastases. Small volume lesions were safely treated with or without prior whole brain radiotherapy.