Abstract P1-07-27: Systematic review of brain metastases in breast cancer in the United States, European Union, and Japan
Authors: Fenske DC , Price GL , Nyhuis AW , Hess LM 
Published: May 2016

Background: Prevalence of brain metastases (BRM) in breast cancer is increasing due to better detection methods and improved patient survival, presenting an unmet need. The exact prevalence is unknown due to a lack of national cancer registries that track BRM cases. Additionally, preceding research presents inconsistent results on survival outcomes, treatment regimens are not well-defined, and there is very limited data on the cost of treating breast cancer BRM. This study was designed to better understand the epidemiology, treatment patterns, cost, and overall survival (OS) of breast cancer patients with BRM in the US, EU, and Japan. Methods: A systematic review following PRISMA guidelines was conducted by searching PubMed, Ovid, and Embase from January 2003 to December 2013. Keywords, MeSH, and Emtree terms were used to define the search strategy. Studies of patients with breast cancer and BRM met eligibility criteria if peer-reviewed, observational, and published in English. Demographic, clinical, and outcomes data were extracted from the publications and entered into Excel. Descriptive statistics were generated with SAS version 9.2. Demographics were summarized, and treatment patterns and median OS were assessed by country. Results: The literature search identified 8,257 articles, of which

245 (n=105,871 breast cancer patients) met eligibility criteria. In these studies, 18,690 breast cancer patients from the US (58.9%), EU (29.5%), and Japan (11.6%) were reported with BRM. Median age of breast cancer patients with BRM was 51.5 years. Patient characteristics are summarized in Table 1. Median OS of breast cancer patients from the time of BRM diagnosis are presented in Table 2. The rate, by country, of radiation therapy among breast cancer patients with BRM ranged from 38.2% to 90.2%, systemic therapy ranged from 5.3% to 46.8%, and surgery was used in 0.8% to 16.2% of studies.

Table 1: Breast Cancer Patient CharacteristicsDemographics of BRM Population(n=18,690)Median Age1 (years)51.5Gender2 (%)Female18,399 (100.0)Male1 (0.0)3Race2 (%)Asian5 (0.4)Black98 (7.1)Hispanic8 (0.6)White1,191 (86.4)Other76 (5.5)Study Enrollment by Country and RegionTotal Studies Reported245Total Breast Cancer Population105,871Total BRM Population (%)18,690EU5,513 (29.5)France3,228 (17.3)Germany812 (4.3)Italy709 (3.8)Spain109 (0.6)UK655 (3.5)Japan2,175 (11.6)US11,002 (58.9)1Reported as the median of medians. 2Not reported in all studies. 3Male breast cancer patient excluded.

Table 2: Reported Median OS1 for Breast Cancer BRM by Treatment Type Systemic TherapyRadiation TherapySurgeryOverallCountryFrance6.906.975.958.17GermanyNR215.0046.0014.00Italy20.4523.6015.5713.50Spain7.755.505.507.75UK5.404.7013.509.50Japan11.408.8010.108.80US10.6011.5011.2011.451Reported in months as the median of medians. 2NR=not reported

Conclusions: Reported median OS and treatment patterns were highly variable across countries. Exposure to risk factors associated with BRM may help explain some of the geographic variability in survival. The lack of published cost data underscores the need to quantify the economic burden of BRM on patients and society.

Citation Format: Fenske DC, Price GL, Nyhuis AW, Hess LM. Systematic review of brain metastases in breast cancer in the United States, European Union, and Japan. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-07-27.