Prescription dose and fractionation predict improved survival after stereotactic radiotherapy for brainstem metastases

Radiation Oncology (Impact Factor: 2.55). 07/2012; 7(1):107. DOI: 10.1186/1748-717X-7-107
Source: PubMed


Brainstem metastases represent an uncommon clinical presentation that is associated with a poor prognosis. Treatment options are limited given the unacceptable risks associated with surgical resection in this location. However, without local control, symptoms including progressive cranial nerve dysfunction are frequently observed. The objective of this study was to determine the outcomes associated with linear accelerator-based stereotactic radiotherapy or radiosurgery (SRT/SRS) of brainstem metastases.

We retrospectively reviewed 38 tumors in 36 patients treated with SRT/SRS between February 2003 and December 2011. Treatment was delivered with the Cyberknife™ or Trilogy™ radiosurgical systems. The median age of patients was 62 (range: 28–89). Primary pathologies included 14 lung, 7 breast, 4 colon and 11 others. Sixteen patients (44%) had received whole brain radiation therapy (WBRT) prior to SRT/SRS; ten had received prior SRT/SRS at a different site (28%). The median tumor volume was 0.94 cm3 (range: 0.01-4.2) with a median prescription dose of 17 Gy (range: 12–24) delivered in 1–5 fractions.

Median follow-up for the cohort was 3.2 months (range: 0.4-20.6). Nineteen patients (52%) had an MRI follow-up available for review. Of these, one patient experienced local failure corresponding to an actuarial 6-month local control of 93%. Fifteen of the patients with available follow-up imaging (79%) experienced intracranial failure outside of the treatment volume. The median time to distant intracranial failure was 2.1 months. Six of the 15 patients with distant intracranial failure (40%) had received previous WBRT. The actuarial overall survival rates at 6- and 12-months were 27% and 8%, respectively. Predictors of survival included Graded Prognostic Assessment (GPA) score, greater number of treatment fractions, and higher prescription dose. Three patients experienced acute treatment-related toxicity consisting of nausea (n = 1) and headaches (n = 2) that resolved with a short-course of dexamethasone.

SRT/SRS for brainstem metastases is safe and achieves a high rate of local control. We found higher GPA as well as greater number of treatment fractions and higher prescription dose to be correlated with improved overall survival. Despite this approach, prognosis remains poor and distant intracranial control remains an issue, even in patients previously treated with WBRT.

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    • "Study Year Patients presenting with symptoms who had improvement after GKRS (%) Kilburn 2014 NR Peterson 2014 NR Jung 2013 32 Sengoz 2013 NR Kawabe 2012 NR Leeman 2012 NR Li 2012 NR Lin 2012 NR Yoo 2011 NR Valery 2011 57 Hatiboglu 2011 NR Kelly 2011 50 Koyfman 2010 NR Samblas 2009 42 Lorenzoni 2009 NR Kased 2008 10 Hussain 2007 9 Fuentes 2006 57 Yen 2006 60 Shuto 2003 NR Huang 1999 50 "
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    ABSTRACT: Metastases are the most common neoplasm of the brain. When these occur in the brainstem, prognosis is poor and treatment options are limited. However, stereotactic radiosurgery has been investigated as a management tool for brainstem metastases. The aim of this review is to gather and summarize data related to the safety and efficacy of stereotactic radiosurgery for the treatment of brainstem metastases. To identify trials for inclusion in this review, a PubMed search using the keywords “stereotactic radiosurgery” and “brainstem metastases” was performed. With this method, we selected 21 series published between 1999 and 2014. Median survival times for these studies averaged 8.3 months (range: 3-16.8 months). Control of systemic disease and performance status were identified as important predictors of survival time. Adjuvant whole-brain radiation therapy was not shown to increase survival. The studies reviewed here report adverse radiation effects at an average rate of 6.7% (range: 0-27%). Stereotactic radiosurgery provides effective local tumor control and may increase survival time for patients with brainstem metastases. Further study is needed to establish dosage guidelines for maximal benefit as well as to evaluate the efficacy of radiosurgery in symptom management.
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