The role of taxanes in HR+ve/HER2-ve metastatic breast cancer (MBC) patients (pts) from adjuvant to metastatic setting in the clinical practice: Results from GIM13-AMBRA study

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Background: The molecular subtypes of BC have individual patterns of behavior, prognosis and sensitivity to treatment, with subsequent implications for the choice of, or indeed role, for adjuvant (Adj) and metastatic chemotherapy (CHT). Taxanes (T) play a central role in chemotherapy for BC. However, previous studies have reported that T are relatively ineffective in patients with Luminal (HR+ve) BC compared with other subtypes. Aim of the present analysis is to describe the use of T in the clinical practice in Italy in HR+ve pts. Methods: AMBRA is a longitudinal cohort study, aiming to describe the choice of first and subsequent lines of treatment in HER2-ve MBC pts receiving at least one CHT (SABCS 2016, P5-15-07 & P5-14-09) in the years 2012-2015. For the present analysis, we focused on the use of T from the AdJ to the metastatic setting. Results: So far, 791/1500 pts have been registered into the study, 651 of them (82,3%) evaluable with HR+ MBC. Main characteristics are: Mean age 52 years; pN: UK 64 (9.8%) N+=405 (62.2%); Adj CHT=397 (61 %), mean DFI=96,99 months. T were used in 60.3% of the cases in the Adj setting, alone or in combination with other drugs, mainly anthracyclines (82.6%), with a mean DFI of 56.9 months. In the metastatic setting, across 1st to 3rd line, 460 pts (70.6%) received T, alone (49.7%) or in combination with Bevacizumab (38.2%), or other CHT drugs (11.9%). Details of the use of T in MBC are described in the table below. Conclusions: T have been used in more than 60% of cases of Luminal tumours in the Adj setting. In this population DFS is significantly shorter as compared with the non-T treated luminal population, as previously suggested by different Authors. Re-challenge with T is very frequent across different lines for MBC. Paclitaxel is the most used T, Docetaxel the less used and Nab-paclitaxel, labelled for MBC only, shows an increasing use from 1st-to 3rd line of treatment. [Table: see text]