Chemotherapy Benefit - EndoPredict® USA

Prediction of Distant Recurrence by EndoPredict in Patients with Estrogen Receptor-Positive, HER2-Negative Breast Cancer who Received Adjuvant Endocrine Therapy plus Chemotherapy (ET+C) or Endocrine Therapy Alone (ET)

Ivana Sestak¹, Miguel Martin², Peter Dubsky³, Federico Rojo⁴, Jack Cuzick¹, Martin Filipits⁵, Amparo Ruiz⁶, William Gradishar⁷, Hatem Soliman⁸, Lee Schwartzberg⁹, Richard Buus¹⁰, Dominik Hlauschek¹¹, Alvaro Rodriguez-Lescure¹², Michael Gnant¹³

1 Centre for Cancer Prevention, QMUL, London, UK; 2 Hospital General Universitario Gregorio Maranon/GEICAM, Madrid, Spain; 3 Klink St. Anna/ABCSG, Lucerne, Switzerland; 4 CIBERONC-ISCII Fundacion Jimenez Diaz/GEICAM, Madrid, Spain; 5
Medical University Vienna/ABCSG, Vienna, Austria; 6 Instituto Valenciano de Oncologia/GEICAM, Madrid, Spain; 7 Robert H. Lurie Comprehensive Cancer Centre of NWU, Chicago, US; 8 H. Lee Moffitt Cancer Center, Tampa, US; 9 West Cancer
Center, Germantown, US; 10 The Breast Cancer Now Toby Robins Research Centre/ICR, London, UK; 8 Austrian Breast and Colorectal Group (ABCSG), Vienna, Austria; 9 Hospital Universitario de Elche/GEICAM, Valencia, Spain

Summary

Chemobenefit validated:
- In over 3,700 patients with ER+, HER2- breast cancer.
- With modern (taxane-containing) treatment regimens.
Patients with a low-risk EndoPredict result did not benefit from the addition of chemotherapy.
Patients with a higher EndoPredict score had a greater benefit from chemotherapy.

Background

EndoPredict (EPclin) is a prognostic test validated for early breast cancer patients with estrogen (ER) receptor positive, HER2-negative disease to help make decisions between 5 years of endocrine therapy alone or with chemotherapy.^1,2,3

Objective

To investigate in a non-randomized setting whether EPclin can predict chemotherapy benefit in pre- and post-menopausal women with ER-positive, HER2-disease who have received five years of endocrine therapy alone (ET) or in combination with chemotherapy (ET+C).

Methods

A total of 3,746 women with ER-positive, HER2-negative disease were included in this analysis.
The primary objective was to evaluate the 10-year distant recurrence-free interval (DRFI) rates as a continuous function of EPclin separately for patients in ET+C and ET.

Results

Patients with a low-risk EndoPredict result did not benefit from the addition of chemotherapy.
Patients with higher EndoPredict scores had a greater benefit from chemotherapy.
Baseline demographics for the two cohorts are shown in Table 1.
Median follow-up for those on ET alone was 9.6 years (IQR 6.0-10.0) vs. 9.2 years (7.5-10.0) for ET+C.
Clear distinction in 10-year risk between ET alone vs ET+C as the EndoPredict score increases (Figure 2).
Interaction between EPclin and treatment was significant (P=0.02).

Conclusions

Patients with a high EPclin score on ET+C had a significantly lower 10-year distant recurrence (DR) risk than those on ET alone.
No differences in 10-year DR risks were observed between ET alone and ET+C for low EPclin scores (<3.3 low risk cut-off).
Interaction between EPclin and treatment was significant (P=0.02).
- Potential benefit of adding chemotherapy to those with high EPclin scores.
Patients with higher EPclin scores have a disproportionate benefit from chemotherapy.
Results give insight into the predictive value of EPclin for women with ER-positive, HER2-negative breast cancer.

References

1. Dubsky et al., 2012; 2. Buus et al., 2017; 3. Martin et al., 2014