Freedom from progression (FFP) by adding paclitaxel (T) to doxorubicin (A) followed by CMF as adjuvant or primary systemic therapy: 10-yr results of a randomized phase III European Cooperative Trial in Operable Breast Cancer (ECTO).

Abstract

537 Background: At the time the ECTO was designed in 1996, taxanes were only indicated for patients with metastatic breast cancer. However, paclitaxel and docetaxel were still to be tested in the adjuvant setting. In addition there was relatively scarce information on the comparative efficacy of neoadjuvant and adjuvant regimens. The ECTO trial was designed to evaluate the addition of paclitaxel to an anthracycline-based adjuvant regimen and to compare this combination with the same regimen given as primary systemic (neoadjuvant) therapy. Methods: A total of 1,355 women with operable breast cancer were randomized to one of three treatments: 1) surgery followed by adjuvant single agent doxorubicin (A) followed by CMF (arm A); 2) surgery followed by adjuvant paclitaxel plus doxorubicin (AT) followed by CMF (arm B); 3) AT followed by CMF followed by surgery (arm C). The two co-primary objectives were to assess the effects on freedom from progression (FFP) of: 1) the addition of paclitaxel to post-operative chemotherapy (arm B versus arm A); and 2) primary versus adjuvant chemotherapy (arm B versus arm C). Results: At 10 years, in the adjuvant setting FFP remained statistically significant in favor of AT followed by CMF (arm B, HR 0.77, P=0.045). Distant FFP was similarly improved but overall survival was not (HR 0.82, P=0.24). There was no significant difference in FFP when chemotherapy was given after surgery compared with the same regimen given before surgery (arm B vs arm C, HR 0.79, P=0.07). In the primary chemotherapy arm, patients who achieved a pathological complete remission (pCR) had improved distant FFP (P < 0.001) compared to patients who did not achieve pCR. When given as primary systemic therapy, the paclitaxel-containing regimen allowed breast-sparing surgery in a significant percentage of patients, which did not translate in an increased risk of ipsilateral breast recurrence compared to the risk observed in patients in the adjuvant arms. Conclusions: Incorporating paclitaxel into anthracycline-based adjuvant therapy resulted in a significantly improved FFP and DFFP.