Background: The ECTO study demonstrated the efficacy of concurrent doxorubicin and paclitaxel (AT) for 4 cycles followed by cyclophosphamyde/ methotrexate/fluorouracil (CMF) for 4 cycles in the neoadjuvant and adjuvant treatment of operable breast cancer (Gianni L. et al. JCO 2009). With the purpose of ameliorating the tolerability of the regimen, we designed the ASTER study to reduce both the duration and the total dose of treatment with AT followed by CMF. Herein we report on the first data of efficacy of the study and the toxicity.

Methods: A total of 345 patients with operable breast cancer were enrolled between September 2008 and November 2011. Median age was 50 years (range 23-74); 74.5% of patients presented with hormonal receptor positive (HR +) and 23,5% of patients with both hormonal receptor negative (HR-PgR-); 19% of patients presented HER2 over expression/amplification; half patients had Ki67 >14%, almost of patients had pT1 (66%) or pT2 (30%) with 27,5% of pN0. Patients were treated with Adriamycin (60 mg/mq) + Paclitaxel (200 mg/mq) q21 for 3 cycles followed by CMF i.v. 1, 8q28 for 3 cycles (73 as neo-adjuvant and 272 as adjuvant regimen). After chemotherapy in patients with HER2+ trastuzumab was delivered for 1 yr and in patients with HR+ tumors hormonal treatment was recommended for 5 yr. Breast irradiation was mandatory after conserving surgery (64% of cases).

Results: At a median follow-up of 36 months, the relapse free survival (RFS) and overall survival (OS) were 92% and 96% respectively. As expected in patients HR+/HER2- RFS were 95% and OS 99%, in patients HER2+ RFS were 90% and OS 97% and in those HR-/HER2- 83% and 79% respectively.

In the neoadjuvant subset tnpCR, defined as the absence of invasive cells in the primary tumor and in nodes, was obtained in 10% of cases. A tnpCR was achieved in 27% of patients with triple negative cancer and only in 5% of HR positive cancer.

Peripheral neuropathy toxicity was reported in 37% of cases and was essentially mild to moderate. Only 8,7% of patients experienced neutropenia G 3, 4,3% GI toxicity G3 and 2,3% mucositis G3. No cardiotoxicity was documented even in the 65 patients who received postoperative trastuzumab to date.

Conclusions: This results of Aster study AT for 3 cycles followed by CMF for 3 cycles showed similar efficacy and very favorable toxicity compared whit our previous experience of eighth cycle of sequential and non cross resistant chemotherapy in early stage breast cancer.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P3-12-13.