Abstract P3-12-05: The BC provincial experience on FEC-D vs. AC-taxane protocol as adjuvant treatment for breast cancer
Authors: Cossetti RD , Tyldesley S , Speers C , Gelmon KA 
Published: August 2014

Background: Despite no direct prospective comparison, FECD and AC-Taxane (ACT) combinations are usually considered equally effective treatment options for early breast cancer. We evaluated the outcomes of patients (pts) in the BCCA database treated with FECD or ACT adjuvant chemotherapy between Jan/06 and Dec/11.

Methods: Female pts with a diagnosis of stage I-III breast cancer were eligible. The primary end-point was RFS (defined as freedom from local, regional or distant recurrence, or breast cancer death without documented recurrence). Secondary end-points were OS, number of cycles, chemotherapy delays, dose reductions, change in chemo protocol, and toxicity profile.

Results: 2013 pts were included: 1137 in the ACT and 876 in the FECD arm. Mean age was 52 (24-79). Baseline characteristics for ACT and FECD were, respectively: ductal histology in 95.5% vs 89.1% and lobular histology in 4% vs 10.6%; tumor size of 0.1-2.0 cm in 37 vs 34%, 2.1-5.0 cm in 50 vs 56% and ≥ 5.1 cm in 11 vs 9%; number of involved nodes were 0 in 42 vs 7%, 1-3 in 32 vs 65%, 4-9 in 16 vs 22% and ≥ 10 in 8 vs 6%; grade 1 in 2% vs 10%, grade 2 in 23% vs 40% and grade 3 in 74% vs 50%; ER/PR positive (+) in 21 vs 85%; ER/PR+/HER2+ in 40 vs 2%, ER/PR negative/HER2+ in 19 vs &lt;1%, and triple negative in 18 vs 11%; local therapy consisted of breast conserving surgery (BCS) in 4 vs 1%, BCS + radiation (RT) in 42 vs 41%, mastectomy (Mx) in 16 vs 6%, Mx + RT in 36 vs 51%, and RT only to 1.5 vs &lt; 1%. ACT and FECD arms showed a 5-year RFS of 84.3% vs 88.2%, and a 5-year OS of 88.2% vs 91.1%, respectively. After adjusting for tumor size, nodal involvement, histology, and LVI, pts in the ACT arm had a higher risk of relapse (HR = 2.269; 95% CI 1.528-3.368), and worse overall survival (HR = 1.796; 95% CI 1.128-2.857) than pts on FECD arm. A total of 815 cases have been reviewed to date for toxicity and chemotherapy delivery. In the ACT (415 pts) and FECD (400 pts) arms, respectively, 96.6% and 98.5% pts received the total number of planned anthracycline cycles, while 91.6% and 88.5% received the total number of planned taxane cycles. There was a dose delay in 36% and 40% of pts, a dose reduction in 30% and 41% of pts, and a change in protocol in 3% and 7% of pts in the ACT and FECD arms, respectively. Chemotherapy-related toxicity events leading to delay, dose reduction and change in protocol occurred in 119 (28.7%) and 216 (54%) pts in the ACT and FECD arms (p 0.01). The number of specific events for the ACT and FECD arms were, respectively: 15 (3.6%) vs 68 (17%) cases of febrile neutropenia, 11 (2.7%) vs 22 (5.5%) cases of grade 3 neutropenia, 46 (11.1%) vs 10 (2.5%) cases of neuropathy, 8 (1.9%) vs 33 (8.3%) cases of mucositis, and 5 (1.2%) vs 2 (0.5%) cases of cardiac toxicity.

Conclusions: Characteristics between arms were imbalanced due to the retrospective nature of the study. After adjustment for risk factors, relapse free and overall survival outcomes were better for the FECD arm. However, FECD had a worse toxicity profile, with a higher rate of life threatening events. The survival benefit was small, and it is possible that uncontrolled differences in prognostic factors that affected the choice for the ACT regimen may have lead to these findings, rather than inferiority of the ACT protocol itself.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P3-12-05.