Gamma Knife surgery for brainstem metastases

Abstract

Object The goal of this study was to assess neuroimaging and clinical outcomes in patients harboring brainstem metastases that were treated with the Leksell Gamma Knife. Methods Twenty-eight patients with brainstem metastases (32 lesions: 8 midbrain, 21 pontine, and 3 medullary) were consecutively treated with GKS. The primary cancer diagnoses in this group included 22 cases of lung cancer, 5 cases of breast cancer, and 1 case of rectal cancer. The median age of the patients was 61 years (range 45–83 years). The median treated lesion volume was 0.78 cm3 (range 0.03–5.6 cm3), and the median GKS margin dose was 16 Gy (range 12–20 Gy). Overall survival in these patients was calculated using the Kaplan-Meier method. Results The median survival time was 9 months after GKS (range 2–32 months). Survival was 39.3% at 1 year and 10.7% at 2 years. The tumor control rate in the series was 90.6% (29 of 32 lesions). Development of peritumoral edema occurred in 1 patient after GKS; 4 months after GKS, the edema disappeared. Conclusions Gamma Knife surgery using a median margin dose of 16 Gy is a safe and effective local therapy for patients with brainstem metastases.

Gamma Knife Treatment of Brainstem Metastases

“…To date, there has not been a randomized controlled trial of GKRS for brainstem metastases compared to palliative care alone or WBRT. Prior studies consist of fourteen retrospective case series published between 1999 and 2014 [2,3,5,6,7,8,9,10,11,12,13,14,15,16]. …”

“…Hong et al analyzed 279 radiosurgery procedures for brain metastases and found that 34% of patients experienced acute, mild to moderate sequelae including headache, seizures, and fluid retention while less than 2% experienced serious adverse effects requiring hospitalization [18]. The average rate of adverse effects reported in previous studies of brainstem metastases is 6% (range 0%–27%) [2,3,5,6,7,8,9,10,11,12,13,14]. This low number may be the result of varied reporting methods among the studies with some reporting only serious events, or it could be that in a short-surviving population such as brainstem metastasis patients, late-arising complications are masked.…”

“…Previous studies have used doses ranging from 13 to 20 Gy and achieved average local control of 89% (range 77%–100%) [2,3,5,6,7,8,9,10,11,12,13,14,15,16]. The long-standing belief that the brainstem is more radiosensitive than the cerebrum seems to be largely based on work done by Boden et al in 1948 [19].…”

“…Several retrospective case series have documented the value of GKRS in treating brainstem metastasis [2,3,5,6,7,8,9,10,11,12,13,14]. GKRS is minimally invasive, effective at sparing tissue that surrounds lesions, and is well tolerated by most patients allowing rapid return to pre-treatment activities.…”

Stereotactic aspiration combined with gamma knife radiosurgery for the treatment of cystic brainstem metastasis originating from lung adenosquamous carcinoma: A case report

“…SRS is the preferred treatment option for brainstem metastases due to its provision of adequate local control with low morbidity. Accurate targeting of the tumor may limit damage to the surrounding healthy brain tissue, thereby mitigating the neurological decline (3,6,15). Between 1999 and 2014, >20 studies reported the clinical characteristics, radiation doses and outcomes of brainstem metastases following SRS treatment (Table I).…”