Abstract P1-13-10: Comparison of overall and recurrence-free survival between four and six cycles of adjuvant docetaxel and cyclophosphamide in early stage breast cancer

Abstract

Abstract Background: The ABC trials and the WSG Plan B trial demonstrated that certain early stage breast cancer patients can be appropriately treated with docetaxel and cyclophosphamide (TC) rather than doxorubicin and cyclophosphamide (AC); however both of these trials utilized six cycles of TC as the comparator. TC is given for 4 cycles based on the US Oncology 9735 trial. To our knowledge, there is no available data that has compared adverse events or outcomes of four versus six cycles of TC. Methods: This was a single-center, retrospective study evaluating recurrence-free survival, overall survival, and occurrence of toxicities between four and six cycles of docetaxel and cyclophosphamide adjuvant chemotherapy for early stage breast cancer at West Virginia University Cancer Institute. Results: 112 patients were included; 81 received four cycles and 31 received six. Recurrence free survival rates of patients that received four and six cycles of chemotherapy were 94% and 90%, respectively, at three years (P=0.68). Overall survival at three years was 99% versus 97% (P=0.49), respectively. The incidence of peripheral neuropathy requiring treatment was 42% in patients that received six cycles and 19% in patients that received four (P=0.015). Conclusion: The addition of two cycles of docetaxel and cyclophosphamide adjuvant chemotherapy for early stage breast cancer provides no additional recurrence-free or overall survival benefit but does increase the incidence of peripheral neuropathy requiring treatment. Table 1.Baseline Characteristics 4 Cycles (n=81)6 Cycles (n=31)P-valueAge, median years (range)57 (37-75)48 (32-71)0.001Receptor status, n (%) 0.63HR positive, HER2 negative61 (75)25 (81) Triple negative20 (25)6 (19) Cancer stage, n (%) 0.031I39 (48)9 (29) II39 (48)17 (55) III3 (4)5 (16) Lymph node involvement, n (%)24 (30)20 (65)0.001Ki67 (%), median (range)23 (2-99)23.5 (4-99)0.99Tumor grade, n (%) 0.07212 (2)4 (13) 242 (52)12 (39) 337 (46)15 (48) Surgery, n (%) Breast conservation35 (43)14 (45)0.99Unilateral mastectomy32 (40)9 (29)0.38Bilateral mastectomy14 (17)8 (26)0.43 Table 2.Adverse Events 4 Cycles (n=81)6 Cycles (n=31)P-valueDose reductions, n (%)17 (21)8 (26)0.62Dose delay, n (%)3 (4)1 (3)0.99Inpatient admissions, n (%)22 (27)8 (26)0.99Treatment for peripheral neuropathy, n (%)15 (19)13 (42)0.015 Citation Format: Mehmi I, Wight CE, Hill JL. Comparison of overall and recurrence-free survival between four and six cycles of adjuvant docetaxel and cyclophosphamide in early stage breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-13-10.