Abstract 1767: Analysis of biomarkers and anthracycline benefit for hormone receptor-negative breast cancer: results from a randomized phase 2 neoadjuvant study (KBOG 1101 Study)

Abstract

Abstract AIM: We compared 6 cycles of docetaxel and cyclophosphamide (TC6) with 3 cycles of 5-fluorouracil and epirubicin and cyclophosphamide followed by 3 cycles of docetaxel (FEC-D) as neoadjuvant chemotherapy for patients with hormone receptor (HR)-negative breast cancer (BC) to identify biomarkers requiring anthracycline treatment. Methods: In total, 103 patients with operable HR-negative BC were administered TC6 or FEC-D. Triple-negative BC was subdivided by CK5/6 and EGFR into basal- and non-basal BCs. The primary endpoint was pathological complete response (pCR). Secondary endpoints were safety, breast-conserving surgery ratio, disease-free survival, overall survival, and predictive factors (Ki-67, P-53, ALDH1 and TOP2A by IHC and TOP2A by FISH) for each regimen. Results: Of the 103 patients, 97 completed the study. Overall pCR was higher for patients treated with FEC-D (36%) than for those treated with TC6 (25.5%) (P=0.265). FEC-D was significantly superior to TC6 in basal BC (42.9% vs 13.6%; P=0.033), while no differences in HER2 and non-basal BCs. Aldehyde dehydrogenase 1 (ALDH1) positivity was inversely associated with pCR for both regimens, significantly for FEC-D (FEC-D: p=0.047, TC6: p=0.085). Patients who achieved pCR tended to have longer DFS (P = 0.287) and OS (P = 0.069). Patients with basal and non-basal BC treated with FEC-D had significantly better DFS (P = 0.016) and OS (P = 0.034) than those with TC6. Conclusion: We found TC6 was less effective than FEC-D for HR-negative BC because it was not sufficient to treat basal-BC. This suggests that DNA damaging agents like anthracyclines are required for treating basal-BC. Additionally, ALDH1 could be a marker for resistance to conventional chemotherapy. Citation Format: Takashi Ishikawa, Kazutaka Narui, Mari S. Oba, Akimitsu Yamada, Kumiko Kida, Mikiko Tanabe, Yasushi Ichikawa. Analysis of biomarkers and anthracycline benefit for hormone receptor-negative breast cancer: results from a randomized phase 2 neoadjuvant study (KBOG 1101 Study) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1767. doi:10.1158/1538-7445.AM2017-1767