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
2840 - Effects of Aerobic and Resistance Exercise on Android:Gynoid Fat Ratio in Breast Cancer Survivors
Presenter: Christina Dieli-Conwright
Session: Poster Display session 2
Resources:
Abstract
869 - Impact of Education for Breast self examination in Rural Indian Women on Early Detection - results of POC study
Presenter: Sneha Parchuri
Session: Poster Display session 2
Resources:
Abstract
1951 - Breast cancer incidence and survival in renal transplant patients: 35-year experience
Presenter: Michalis Kontos
Session: Poster Display session 2
Resources:
Abstract
2017 - The changing landscape of breast cancer incidence after treatment for Hodgkin’s disease
Presenter: Amelia Benjamin
Session: Poster Display session 2
Resources:
Abstract
1780 - Number of deliveries as a prognostic factor in different breast cancer subtypes
Presenter: Anniina Jääskeläinen
Session: Poster Display session 2
Resources:
Abstract
4650 - Effects of supervised and adapted exercise program in the quality of life and strength of breast cancer survivors: MAMA MOVE Gaia trial
Presenter: Ana Joaquim
Session: Poster Display session 2
Resources:
Abstract
4962 - Study On the Socioeconomic and Clinical Factors Affecting the Proportion of Breast Conserving Surgery in Chinese Women Breast Cancer
Presenter: Jin Zhang
Session: Poster Display session 2
Resources:
Abstract
5451 - Clinical decision making and multidisciplinary team meetings (MDMs) in early breast cancer. Is the agreement between planned and applied therapeutic program?
Presenter: Marco Giavarra
Session: Poster Display session 2
Resources:
Abstract
888 - The value of genetic counselling in breast cancer genetic testing and clinical management
Presenter: Vicki Kiesel
Session: Poster Display session 2
Resources:
Abstract
4005 - Elderly patients in the Japanese Breast Cancer Registry
Presenter: Masataka Sawaki
Session: Poster Display session 2
Resources:
Abstract