by Debora Basile, Lorenzo Gerratana, Carla Corvaja, Giacomo
Pelizzari, Giorgia Franceschin, Elisa Bertoli, Lorenza Palmero, Diego Zara,
Martina Alberti, Silvia Buriolla, Lucia Da Ros, Marta Bonotto, Mauro Mansutti,
Simon Spazzapan, Marika Cinausero, Alessandro Marco Minisini, Gianpiero Fasola,
Fabio Puglisi
The Breast: VOLUME 57, P104-112, JUNE
01, 2021 (Published: March 11, 2021)
Background
Endocrine therapy (ET) plus cyclin-dependent-kinases 4/6
inhibitors (CDK4/6i) represents the standard treatment for luminal-metastatic
breast cancer (MBC). However, prospective head-to-head comparisons are still
lacking for 1st line (L) options, and it is still crucial to define the best
strategy between 1st and 2nd L.
Materials and methods
717 consecutive luminal-MBC pts treated between 2008 and
2020 were analyzed at the Oncology Department of Aviano and Udine, Italy.
Differences about survival outcomes (OS, PFS and PPS) were tested by log-rank
test. The attrition rate (AR) between 1st and 2ndL was calculated.
Results
At 1stL, pts were treated with ET (49%), chemotherapy (CT)
(31%) and ET-CDKi (20%) while, at 2ndL, 33% received ET, 33% CT and 8% ET-CDKi.
Overall AR was 10%, 7% for CT, 8% for ET and 17% for ET-CDKi. By multivariate
analysis, 1stL ET-CDK4/6i showed a better mPFS1 and OS. Moreover, 2ndL
ET-CDK4/6i demonstrated better mPFS2 compared to ET and CT. Notably, 1stL
ET-CDKi resulted in higher mPFS than 2ndL ET-CDKi. Intriguingly, 1stL
ET-CDK4/6i was associated with worse mPPS compared to CT and ET. Secondarily, 1stL
ET-CDK4/6i followed by CT had worse OS compared to 1stL ET-CDK4/6i followed by
ET. Notably, none of baseline characteristics at 2ndL influenced 2ndL treatment
choice (ET vs. CT) after ET-CDKi.
Conclusion
Our real-world data demonstrated that ET-CDKi represents the
best option for 1stL luminal-MBC compared to ET and CT. Also, the present study
pointed out that 2ndL ET, potentially combined with other molecules, could be a
feasible option after CDK4/6i failure, postponing CT on later lines.
