Abstract 192P
Background
NACT has been introduced to facilitate less invasive surgery and to obtain better prognostication and guidance regarding post neoadjuvant therapy. Here we describe the outcome from NACT in an unselected Danish cohort of TNBC regarding pCR, node-conversion, and surgical procedure.
Methods
This study is a retrospective nationwide cohort-study based on real-world data. Before initiation of NACT eligible patients were between 1/1-2016-31/12-2019 prospectively registered in the Danish Breast Cancer Group clinical database. Exclusion criteria were LABC, metastatic disease or prior malignancy. In total 488 patients were included and examined by treatment response based on pre- and post-NACT characteristics, surgical procedure and chemotherapy. pCR was defined as no residual invasive tumor in the breast or in the axillary nymph nodes (ypT0/Tis ypN0(i-)). Patients were grouped into 2 primary chemotherapy regimens, with either 3+3 or 4+4 series with epirubicin and cyclophosphamide (3qw) followed by a taxane (docetaxel (3qw) or weekly paclitaxel).
Results
Median age was 52 years (range 24-82). Pre-NACT tumor size was divided into 3 groups, 0-2 cm (11.7%), 2-5cm (73.0%) and 5cm or larger (11.3%). The remaining 4% were unknown. Patients were allocated to receive 3+3 (49%) or 4+4 (37%) series depending on tumor size. The remaining 14% received another combinational chemotherapy regimen. Overall, 151 (31%) achieved pCR. Among patients with biopsy verified node-positive pre-NACT 49% had tumor-free axillary nodes post-NACT. The majority received breast-conserving surgery (BCS; 56%) or mastectomy (37%) and in 7% definitive surgery was unknown.
Conclusions
Surgery was reduced in more than half of the patients either by converting mastectomy to BCS or by avoiding axillary dissection. However, only 31% achieved a pCR and consequently we will in the future consider more effective chemotherapy regimens.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
Danish Breast Cancer Group.
Funding
Danish Breast Cancer Group.
Disclosure
W.W. Thomassen: Financial Interests, Personal, Funding, Unristricted research grant: Danish cancer cociety. T. Berg: Financial Interests, Institutional, Research Grant: Danish cancer cociety; Financial Interests, Institutional, Research Grant: Neye Fonden; Financial Interests, Institutional, Research Grant: Roche; Financial Interests, Institutional, Research Grant: Novartis; Financial Interests, Institutional, Research Grant: Samsung Bioepis; Financial Interests, Institutional, Research Grant: Pfizer; Financial Interests, Personal, Invited Speaker: Pfizer; Financial Interests, Institutional, Research Grant: AstraZeneca; Financial Interests, Institutional, Research Grant: Merck Eisai; Financial Interests, Institutional, Research Grant: Venture Oncology; Financial Interests, Personal, Advisory Board: Merck. M. Jensen: Financial Interests, Institutional, Research Grant: Samsung Bioepis; Financial Interests, Institutional, Research Grant: Nanostring Technologies; Financial Interests, Institutional, Research Grant: Oncology Venture. B. Ejlertsen: Financial Interests, Institutional, Research Grant: Nanostring Technologies; Financial Interests, Institutional, Research Grant: AstraZeneca; Financial Interests, Institutional, Research Grant: Novartis; Financial Interests, Institutional, Research Grant: Oncology Venture; Financial Interests, Institutional, Research Grant: Pfizer; Financial Interests, Institutional, Research Grant: Roche; Financial Interests, Institutional, Research Grant: Samsung Bioepisis.