Combination or sequential single agent for the treatment of metastatic breast cancer (MBC) patients (pts). Impact of further chemotherapy (CT) in overall survival (OS) in the Alamo registry

Abstract #2121 Introduction: Combinations can improve OS in MBC; however sequential single agent is sometimes preferred. In a recent report, pts receiving paclitaxel monotherapy in first line had a significantly worse OS if they were not receiving post study CT (PSC); no difference was seen in pts receiving paclitaxel+gemcitabine (Llombart, EBCC 2008). In this trial only 58% of pts received PSC. Purpose: To assess, outside the context of a clinical trial, the amount of MBC pts receiving CT beyond first line, as well as the impact of combination use and further CT lines in their OS. Methods: Alamo 1-2 is a breast cancer patient registry run by the GEICAM. 15482 pts diagnosed from 1990-1997 in 54 sites were included in the database. 4668 pts were stage IV; 778 (16.7%) metastatic at diagnosis and 3890 (83.3%) have had a recurrence. Results: 3045 (65%) pts received CT in first line, 83% were combinations (with anthracyclines 42%, CMF 16%, taxane+anthracyclines 9.4% or +other agents 8%) and 16% were monotherapy. Among other variables studied, only previous treatment (in early stage) was influencing the choice of a combination (pts without previous CT received more combinations than pts receiving CMF, than pts receiving anthracyclines). Median survival for pts receiving single agent was significantly shorter compared to pts receiving combination, 16.2 and 21.85 months (m) respectively, HR=1.37 (IC 95%: 1.21-1.55; p 65, negative hormonal receptor status, hepatic disease, Grade 3 and ≥ 3 disease sites. Half of the pts never received further CT after first line treatment. Only age and number of disease sites were influencing this decision in the Cox multivariate model. Median survival was 24.9 m in pts receiving further CT and 14.5 m in the ones not receiving it. In pts not receiving further CT, median OS was significantly shorter if they were treated with single agent in first line in comparison to those receiving previous combination: HR= 1.59 (IC 95%: 1.33-1.89; p< 0,00001). This difference was not significant in pts receiving further CT: HR= 1.15 (IC 95%: 0.97-1.37; p=0.101). Conclusion: Our data show that only half of the MBC pts receive further CT after first line; they have longer survival. We found significant evidence that further CT is impacting the OS in pts treated with single agent in first line, but not in those receiving previous combination. Those facts should be taken into consideration when selecting single agent or a combination in first line. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 2121.