Outcomes after radiation therapy for brain metastases from gastrointestinal primaries.

Abstract

647 Background: There is limited data regarding outcomes of patients with colorectal cancer (CRC) and other gastrointestinal (GI) cancers metastatic to the brain. The aim of this study is assess intracranial disease control in GI patients treated with radiation therapy (RT) and the likelihood of receiving systemic therapy following the diagnosis of metastatic disease to the brain. Methods: From 1/2007 to 6/2013, 24 consecutive patients with adenocarcinoma of a GI primary were treated with RT for brain metastases. Patients were excluded if they had prior RT to the brain. The majority of patients had CRC (n = 15). Ten patients had resection of at least one brain tumor prior to radiation therapy. Patients were treated with the following RT modalities: stereotactic radiosurgery alone (n = 12), whole brain RT (n = 7), both (n = 1), and partial brain RT (n = 1). Survival and control rates were analyzed by the Kaplan-Meier method. Results: Twenty-one patients had died at the time of analysis and the median overall survival was 5.4 months (range, 0.5 – 58 months). Radiographic follow up was available in 20 patients and 60% (12/20) had intracranial disease progression. The 6- and 12-month control rates for the treated tumors were 60% and 30%, respectively. Seven patients received salvage radiation therapy following intracranial disease progression. Fifty-eight percent (14/24) did not receive further systemic therapy. On univariate analysis, only prior surgical resection predicted for improved survival (3.8 vs. 7.8 months, p = 0.018), while number of lesions, performance status, primary site, chemotherapy after RT, and RT modality were not significant. Conclusions: Survival and intracranial disease control following RT for brain metastasis from GI cancers are poor and many patients do not receive further systemic therapy. In this small series, outcomes are worse than published series for other disease sites metastatic to the brain and further research is warranted.