Adjuvant Gamma Knife radiosurgery following surgical resection of brain metastases: a 9-year retrospective cohort study

Abstract

Given the potential morbidity of whole brain radiation therapy (WBRT), there has been an increasing trend to defer WBRT and deliver Gamma Knife stereotactic radiosurgery (GKS) to cerebral metastatic lesions. We analyzed our experience delivering GKS to the tumor cavity following surgical resection of brain metastases and compared our results to patients receiving WBRT after surgical resection of a metastatic lesion. We performed a retrospective review of patients undergoing surgical resection of at least one brain metastasis between December 1999 and December 2008. Both univariate and multivariate Cox proportional hazards regression were utilized to analyze the influence of various prognostic factors on survival. Twenty-five patients had a metastatic lesion resected followed by adjuvant GKS to the resection cavity while another 18 had surgical resection followed by WBRT. Aside from a disparity in gender distribution (72% of GKS patients were female while women only constituted 28% of the WBRT group), no significant differences existed between groups. The median survival for patients receiving GKS was 15.00 months as compared to 6.81 months among those receiving WBRT (P = 0.08). Univariate Cox regression analysis identified the number of metastases (HR 1.65, 95% CI 1.07-2.54, P = 0.02) and regional recurrence (RR 5.23, 95% CI 1.78-15.38, P = 0.003) as poor prognostic factors. Multivariate regression analysis showed that regional recurrence (HR 5.17, 95% CI 1.69-15.78, P = 0.004) was again strongly associated with worse survival. Although limited by the retrospective nature of our study and lack of some clinical measures, patients undergoing GKS to the resection cavity had a trend towards longer median survival.

Phase I/II Study of Neurosurgical Resection and Intraoperative Cesium-131 Radio-isotope Brachytherapy in Patients With Newly Diagnosed Brain Metastases

“…4,15,18,[23][24][25]27,28,30,31,35,39,48,50,55 Intracranial distant failure was reported in 44-65% at 1 year, and death due to neurologic causes in ~25%. 4,15,18,[23][24][25]27,28,30,31,35,39,48,50,55 The typical time frame for the delivery of post-operative SRS is between 2-6 weeks following the surgical resection. This buffer time is needed in order to allow adequate wound healing following the surgery and to allow the cavity to shrink to a smaller, stable size in preparation for radiosurgery targeting.…”

“…Among such options are post-op SRS 4,15,18,[23][24][25]27,28,30,31,35,39,48,50,55 and intraoperative application of either permanent low-dose 7,12,22,52 or temporary highdose 5,40,44,51,61 radio-isotopes (generally Iodine-125 (I-125)) into the surgical cavity. Postop SRS is the more commonly used of these treatment modalities due to its wider availability.…”

The History of Stereotactic Radiosurgery Development and Its Role in the Treatment of Brain Metastases

“…Как обсуждалось выше, это улучшение внутричерепного контроля опухоли не отражается на увеличении выживаемости или сни-жении неврологической смертности. Это подтверждает наблюдение из большого многоцентрового ретроспек-тивного исследования [39], в котором комбинирование ТОГМ и СРХ не привело к улучшению выживаемости. Следует отметить, что при появлении новых церебраль-ных метастазов можно легко провести 2-й курс СРХ, что устраняет какое-либо преимущество первоначаль-ного улучшения внутричерепного контроля.…”

“…Серия исследований [39,46,47] показала, что проведение одной либо нескольких фракций приводит к уровню местного контроля, не от-личающемуся от такового при ТОГМ. При таком под-ходе субклиническая болезнь в других отделах головно-го мозга не рассматривается и, таким образом, рецидивы в других участках мозга появляются чаще.…”

Outcomes Following Gamma Knife for Metastases

“…Only one retrospective study directly comparing resection+SRS with resection+WBRT has been published (Hwang, 2010). For the 43 patients (25 GK-SRS vs. 18 WBRT) treated at Tufts following tumor resection, there were non-significant trends towards superior survival for patients receiving GK-SRS (15 vs. 7 months, p=0.008) and local control (100% vs. 83%).…”