Final Result of Non-Anthracycline Containing Weekly Paclitaxel Plus Carboplatin Regimen as Neoadjuvant Chemotherapy for Breast Cancer.

Abstract

Abstract Background: Neoadjuvant chemotherapy (NCT) has become an important part in the comprehensive treatment of breast cancer, patients classified with pathological complete remission (pCR) after NCT have superior outcome. A single center, prospective phase II study was initiated to evaluate the activity and safety of non-anthracycline-containing weekly PCb regimen in NCT for breast cancer, which may help our further clinical usage and research.Materials and Methods: Eligible patients with clinical stage IIA∼IIIC breast cancer were assigned to receive four cycles of PCb with the dose of P (Paclitaxel) 80mg/m2 and Cb (Carboplatin) AUC=2, given day 1, day 8 and day 15, out of every 4 weeks. Clinical response and extent of residual disease in breast and axillary lymph nodes (ALN) in surgical removed sample were assessed after completion of NCT. pCR was defined as no invasive cancer in breast and axillary. Estrogen(ER), Progesterone (PR) receptor and HER2 status were detected before treatment by immunohistochemistry, HR (hormonal receptor) was defined positive as either or both ER/PR positive.Results: From Dec. 2007 to Dec. 2008, 107 breast cancer patients received weekly PCb NCT and one with bilateral breast cancer. 85.2% patients were initially diagnosed with stage III diseases, 83 patients had positive ALN confirmed by fine needle aspiration before NCT. 94.4% (102) patients have completed all of 4 cycles weekly PCb treatment. Clinical response rate was 86.1% with clinical complete remission rate 32.4%. 21 patients achieved pCR, with pCR rate 19.4%. 30 cases who had positive ALN before NCT showed negative result in the surgery specimen with ALN downstage rate 36.6%. The incidence of grade 3-4 neutropenia was 40.2% and only 1 patient was reported with febrile neutropenia. Severe thrombocytopenia and anemia occurred in 0.9% and 4.7% of patients, respectively. Peripheral neuropathy was frequent, but never severe, only 5 (4.7%) patients recorded had more than grade 1 toxicity. Patients with ER- disease had superior pCR rate than ER+ patients (32.6% vs. 9.7%, P=0.005). Patients with PR- disease had higher pCR rate than PR+ patients (30.6% vs. 10.2%, P=0.010). pCR rate was 33.3% (8/24) and 15.5% (13/84) in HER2+ and HER2- patients. Furthermore, We used ER, PR and HER2 status to construct molecular classification of breast cancer, patients classified with Luminal A (HR+/HER2-) subtype had the lowest pCR rate, which was 8.3% less than 22.2% in Luminal B (HR+/HER2+), 33.3% in triple-negative (HR-/HER2-) and 40.0% in HER2 positive (HR-/HER2+) subtype patients, P=0.017.Conclusions: Weekly PCb regimen was very active and tolerable as NCT for breast cancer. ER-, PR-, HER2+ and triple negative breast cancer were more likely to achieve pCR. This weekly PCb regimen should consider as a reasonable non-anthracycline-containing option in NCT setting of breast cancer. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 1099.