Linear accelerator-based stereotactic radiosurgery for brainstem metastases: the Dana-Farber/Brigham and Women’s Cancer Center experience

Abstract

To review the safety and efficacy of linear accelerator-based stereotactic radiosurgery (SRS) for brainstem metastases. We reviewed all patients with brain metastases treated with SRS at DF/BWCC from 2001 to 2009 to identify patients who had SRS to a single brainstem metastasis. Overall survival and freedom-from-local failure rates were calculated from the date of SRS using the Kaplan-Meier method. Prognostic factors were evaluated using the log-rank test and Cox proportional hazards model. A total of 24 consecutive patients with brainstem metastases had SRS. At the time of SRS, 21/24 had metastatic lesions elsewhere within the brain. 23/24 had undergone prior WBRT. Primary diagnoses included eight NSCLC, eight breast cancer, three melanoma, three renal cell carcinoma and two others. Median dose was 13 Gy (range, 8-16). One patient had fractionated SRS 5 Gy ×5. Median target volume was 0.2 cc (range, 0.02-2.39). The median age was 57 years (range, 42-92). Follow-up information was available in 22/24 cases. At the time of analysis, 18/22 patients (82%) had died. The median overall survival time was 5.3 months (range, 0.8-21.1 months). The only prognostic factor that trended toward statistical significance for overall survival was the absence of synchronous brain metastasis at the time of SRS; 1-year overall survival was 31% with versus 67% without synchronous brain metastasis (log rank P = 0.11). Non-significant factors included primary tumor histology and status of extracranial disease (progressing vs. stable/absent). Local failure occurred in 4/22 cases (18%). Actuarial freedom from local failure for all cases was 78.6% at 1 year. RTOG grade 3 toxicities were recorded in two patients (ataxia, confusion). Linac-based SRS for small volume brainstem metastases using a median dose of 13 Gy is associated with acceptable local control and low morbidity.

Local control after fractionated stereotactic radiation therapy for brain metastases

“…Furthermore, the threshold for toxicity of critical structures such as the optic apparatus also limits the dose that can be safely administered near these areas [7][8][9]. Likewise, while brainstem SRS is commonly used including at our institution [10], the doses tend to be somewhat lower than the doses used in other regions of the brain due to toxicity concerns [10][11][12][13], and there appear to be higher risks of complications with lesion volumes greater than 1 cc [12,13]. While WBRT can be used when lesions are felt less suitable for SRS, local therapy may still be preferable in many cases, since the addition of WBRT has not been associated with a survival advantage in addition to local therapy, and is associated with greater short and longterm side effects [14].…”

Radiosurgery for brainstem metastases with and without whole brain radiotherapy: clinical series and literature review

“…Lorenzoni et al identified that doses above 18 Gy predicted improved overall survival, and Trifiletti et al and Kased et al both demonstrated that doses of 16 Gy and above resulted in improved local control [16, 25, 28]. Other studies did not find marginal dose as an important predictor for local control or overall survival in patients treated with SRS for brainstem metastases [18, 19, 21, 24, 26]. Despite the majority of our patients receiving a lower marginal prescription dose of 15 Gy compared with other studies, local control was 78.6 % at 1 year in our series compared with at least 74 to 88 % in other series.…”

A Review of the Clinical Outcomes for Patients Diagnosed with Brainstem Metastasis and Treated with Stereotactic Radiosurgery

“…Hatiboglu et al [1] report that twelve of their patients developed fifteen complications due to LINAC-based SRS with serious neurological deficits occurring in two patients (hemiparesis in one patient and hemiparesis and cranial nerve deficit with hemorrhage in another). Kelly et al [12] assert that two patients acquired RTOG grade three toxicities in response to LINAC based SRS, confusion in one and ataxia in the other. Gamma Knife SRS performed by Koyfman et al [5] yielded no grade three or four toxicities; however, weakness, ataxia, and bleeding were observed in three patients.…”