Abstract P6-14-16: A Systematic Review of the Evidence for Treatment of Metastatic Breast Cancer beyond 2nd Line

Abstract

Abstract Background: Optimal treatment of metastatic breast cancer (MBC) post second-line is not well defined. Therapy options are limited by previous exposure, while HER2 status may remain relevant to decision-making. A systematic review was conducted to identify trials reporting efficacy data, and review the current treatment landscape for HER2+ and - patients for third and later line treatment of MBC. Methods: A systematic search strategy from Medline, EMBASE and Cochrane (CCTR) databases retrieved citations for two-stage review. Citations that reported 3rd or later line treatment of MBC patients were included. Selected conference proceedings from the last 3-5 years were searched for relevant abstracts and posters. Included studies were restricted to those with data reported for 10 or more patients. Results: 39 citations from 29 trials, investigating 22 treatment regimens, were identified which reported efficacy data specific for a 3rd or later line population: in 22 trials, this was a sub-group analysis of a mixed line population. 76% of included studies were single arm: only 1 RCT was identified. 21% of included studies investigated the treatment of HER2+ populations; no studies reported outcomes specific for the HER2- population. Overall response rate (ORR) was the most reported outcome. The majority of responses were partial, complete response was rarely observed beyond 2nd line. Overall and progression-free survival were rarely reported. The highest ORR was reported for mitomycin C and capecitabine in HER2 mixed patients. Table 1 presents response rates reported in HER2+ patients. Conclusions: There does not appear to be a standard regimen used in the treatment of patients beyond the second line. In patients with HER2+ breast cancer, T-DM1 had the highest reported response rate. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P6-14-16.