Abstract 5876
Background
Recently, CDK4/6i proved to improve the efficacy of HT of pts affected by luminal MBC. However, the best sequence of HT is still unclear and it is still uncertain if pts with lobular histology derive the same benefit of ductal when receiving second line CDK4/6i. Particularly in lobular MBC, the dysregulation of the AKTpathway with the overexpression of cyclin E potentially represents an important mechanism of acquired resistance to HT, finally providing an intrinsic resistance to subsequent CDK4/6i. Thus, a multicentric retrospective study was conducted to determine the efficacy of PALBO-FUL versus EVE-EXE as second line HT of MBC with Lobular histology.
Methods
Pts affected by Lobular MBC receiving PALBO-FUL or EVE-EXE for second line HT from 2013 to 2018 in 6 Italian centers were considered eligible. The primary endpoint was progression free survival (PFS). A propensity score (PS) adjustment for baseline characteristics was further accomplished for survival analysis.
Results
Seventy-four of 376 screened pts were diagnosed for Lobular MBC; 48pts received PALBO-FUL, whereas 26 were treated with EVE-EXE, without imbalance in clinical characteristics. PFS resulted to be significantly longer for pts receiving EVE-EXE in comparison with PALBO-FUL (6.1 vs. 4.5 months, univariate HR 0.58, 95% CI 0.35-0.96; p = 0.025). Previous chemotherapy exposure resulted to be significantly associated with PFS at the multivariate analysis (HR 0.41, 95% CI 0.24-0.72, p = 0.002). At the PS analysis, adjusted for previous chemotherapy exposure and synchronous/metachronous metastatic status, PFS was confirmed to be significantly longer for pts receiving EVE-EXE in comparison with PALBO-FUL (6.0 vs. 4.6 months, p = 0.04).
Conclusions
This retrospective real-world analysis generates the hypothesis of a potential benefit of EVE-EXE in comparison with PALBO-FUL for second line HT of MBC with Lobular histology, and it allows to speculate on the best therapeutic sequence. Nevertheless, the small pts’ sample calls for a larger and adequately sized prospective validation.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.
Resources from the same session
1058 - Assessment of CPS+EG, Neo-Bioscore and modified Neo-Bioscore in breast cancer patients treated with preoperative systemic therapy: a multicenter cohort study
Presenter: LING XU
Session: Poster Display session 2
Resources:
Abstract
1156 - The concordance of treatment decision guided by Oncotype and the PREDICT tool in early stage breast cancer
Presenter: Hadar Goldvaser
Session: Poster Display session 2
Resources:
Abstract
3447 - Influence of first treatment delay on survival among breast cancer subtypes
Presenter: Irene Zarcos Pedrinaci
Session: Poster Display session 2
Resources:
Abstract
3505 - Clinical features of early-stage (I-III) triple-negative breast cancer (TNBC) patients with tumors exhibiting low-overall change in molecular profile after neoadjuvant therapy.
Presenter: Nour Abuhadra
Session: Poster Display session 2
Resources:
Abstract
5442 - Meta-analysis in HER2+ early breast cancer therapies and cost-effectiveness in a Brazilian perspective
Presenter: Marcos Magalhaes
Session: Poster Display session 2
Resources:
Abstract
1570 - Anti-mullerian hormone (AMH) levels and antral follicle counts (AFC) may predict ovarian reserves before systemic chemotherapy (SC) in women with breast cancer(BC); a prospective clinical study
Presenter: Cetin Ordu
Session: Poster Display session 2
Resources:
Abstract
2698 - Prognosis of selected triple negative apocrine breast cancer patients who did not receive adjuvant chemotherapy.
Presenter: Giuseppe Cancello
Session: Poster Display session 2
Resources:
Abstract
3104 - Novel Blood Based Circulating Tumor Cell Biomarker For Breast Cancer Detection
Presenter: Chun-Yu Liu
Session: Poster Display session 2
Resources:
Abstract
4631 - Multi-Gene Prognostic Signatures and Prediction of Pathological Complete Response of ER-Positive HER2-Negative Breast Cancer Patients to Neo-Adjuvant Chemotherapy
Presenter: Claudia Mazo
Session: Poster Display session 2
Resources:
Abstract
4632 - Impact of menopause status on breast cancer outcomes and amenorrhea incidence during adjuvant tailored dose dense chemotherapy
Presenter: Andri Papakonstantinou
Session: Poster Display session 2
Resources:
Abstract