Comparing Disease Outcome of Women with Hormone Receptor-Negative/Her2-Positive (Hr-/Her2+) or Triple Negative (Tn) Metastatic Breast Cancer (Mbc) Receiving Multiple Lines of Chemotherapy: a Mono-Institutional Retrospective Analysis

Aim: Current guidelines recommend HER2 blockade across subsequent chemotherapy (CT) lines to provide effective control of HER2+ MBC, while the benefit deriving from multiple lines in patients (pts) with triple negative (TN) disease is uncertain. We sought to evaluate outcome of women affected with HR-/HER2+ or TN disease receiving multiple lines for their MBC, aiming to identify potential prognostic and/or predictive factors for treatment response and disease outcome. Methods: We evaluated 460 women who had received CT for metastatic disease from February 2004 to January 2011 at our Institution: 250 were affected with ER-/PR-/HER2+ (cohort A) and 210 with TN disease (cohort B).The overall survival (OS) for each woman was calculated from day 1 of 1st CT line to death or last follow-up, according to Kaplan-Meyer method. Association between baseline characteristics and OS were assessed using Cox proportional hazards model. Results: With cut-off data analysis as to March 2013, the median follow-up was 65 months (range 21-122). Median number of given CT lines was 3 (range 1-10); the percentages of pts receiving 2, 3, ≥4 lines of CT were 89%, 52%, 32% (cohort A) and 72%, 27%, 17% (cohort B), respectively. Median OS, evaluated from day 1 of 1st CT line, decreased from 28.6 months (1st line) to 6.7 months (≥4 lines) in cohort A, and from 10.2 to 3.8 months in cohort B. When calculated in function of the total number of lines received, survival increased from 28.6 (1st line) to 34.6 months (≥4 lines) in cohort A, and from 10.2 to 16.2 months in cohort B. In univariate analysis absence of liver metastasis, prior adjuvant trastuzumab and taxane exposure were factors positively linked to a longer OS in cohort A and B, respectively. In multivariate analysis the number of received CT lines resulted independent predictor of longer OS in both the cohorts (p = 0.003 and p Conclusions: Results of our analysis confirm that prognosis of women with TN MBC remains poor also when compared with outcome of other unfavorable tumor subtypes, as HR-/HER2+ disease. The observed OS benefit as a function of total number of CT lines received supports the concept that each treatment line could determine a survival gain also in this ‘difficult to treat’ patient population. Disclosure: All authors have declared no conflicts of interest.