115P - Longterm prognostic utility of MammaPrint® (MP) by clinical and genomic risks, including Ultralow (gUL) risk patients (pts)

Background

In the MINDACT trial, 4 risk categories (RC) by clinical (c) and genomic (g) risks were defined. In cHigh/gLow risk patients (pts) with no adjuvant chemotherapy (CT), 8y-Distant Metastases Free Survival (DMFS) was 89.4 % [95% CI 86.2-91.5]. MP also identified a third subgroup of gUL pts (score 0.355 – 1.0, 15% in MINDACT), with an excellent prognosis and no benefit from extended endocrine therapy (EET). We aimed to study: DFS/ DMFS by the 6 RC resulting from combining the 2 (c) categories with the 3 (g) groups; the timing of recurrences; and the putative benefit of EET for each genomic group.

Methods

All ER+/HER2- BC pts with MP data diagnosed between 2012-2017 at Vall d'Hebron University Hospital were selected. cLow risk was defined as in MINDACT trial. To study the benefit of EET, a landmark analysis at 5y from ET initiation was conducted.

Results

140 pts were identified. Baseline features: 47.8% premenopausal; stage I/II: 74%/26%; histological grade 1/2/3: 19.6%/74.9%/6.5%. cLow/cHigh: 67%/33%; gUL/gLow-Non-Ultralow (LNUL)/gHigh: 11.4%/53.6%/35%. PgR and Ki67 tended to correlate with MP g risks, but only the IHC-subtype reached statistically significance. Systemic adjuvant treatments [N/%]: ET 138/98.5%; ovarian function suppression for premenopausal pts 23/35%; CT: 45/32%; EET: 49/35.8%. After 8y-median FU, 15 DFS events and 11 DMFS were observed. DMFS in cHigh/gLow (UL+LNUL) without CT was 90.6% [81.1%; 100%]. DFS/DMFS rates by each c/g category are depicted in the table. Only 4 DMFS events occurred after 5 years, precluding to explore EET role by RC Table: 115P

Conclusions

In our series, DMFS rate in cHigh-gLow pts without CT was similar to that reported in MINDACT trial. In line with prior reports, gUL pts had excellent survival, while cHigh-gHigh group showed significantly poorer outcome. Albeit limited by small sample size, classification in 6 RCs instead of 4 seems useful to redefine prognosis. Additional FU is warranted to determine the EET benefit in each RC.

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

E. Zamora: Financial Interests, Personal, Invited Speaker, Review session for medical oncologists: Eisai, Lilly; Other, Registration to ESMO Congress 2022 (virtual): Novartis; Other, Registration to: Eisai. I. Pimentel: Financial Interests, Personal, Invited Speaker: MSD, Novartis, AstraZeneca; Non-Financial Interests, Member, ASCO member: ASCO; Other, travel and accommodations expenses: Phyzer. M. Cruellas Lapena: Financial Interests, Institutional, Invited Speaker: ROCHE. G. Villacampa: Financial Interests, Personal, Invited Speaker, Invited speaker in a course: MSD; Financial Interests, Personal, Advisory Board: AstraZeneca; Financial Interests, Personal, Invited Speaker, Invited speaker in an internal training: Pierre Fabrer, GSK; Financial Interests, Personal, Invited Speaker, Internal discussion about the interpretation of some published results: Pfizer; Financial Interests, Personal, Other, Collaborations with specific projects: Reveal Genomics. M. Oliveira: Financial Interests, Personal, Advisory Board: AstraZeneca, Daiichi Sankyo / AstraZeneca, Gilead, Pierre Fabre, Roche, Seagen, iTEOS, Relay Therapeutics; Financial Interests, Personal, Invited Speaker: Gilead, MSD, Novartis, Pfizer, Roche, Seattle Genetics, AstraZeneca; Financial Interests, Institutional, Invited Speaker: AstraZeneca, Boehringer-Ingelheim, GSK, Roche, Seattle Genetics, Zenith Epigenetics, Gilead, Ayala Pharmaceuticals; Financial Interests, Invited Speaker: Roche; Non-Financial Interests, Invited Speaker: SOLTI Breast Cancer Research; Other, Travel Grant: Pierre Fabre, Eisai, Gilead, AstraZeneca. C. Saura Manich: Financial Interests, Personal, Advisory Board: AX'Consulting, AstraZeneca, Daiichi Sankyo, Eisai, Exact Sciences, Exeter Pharma, F. Hoffmann - La Roche Ltd., Gilead, ISSECAM, Lilly, MediTech, Medical Statistics Consulting, Merck Sharp & Dohme, Novartis, Pfizer, Philips, Piere Fabre, PintPharma, Puma, Roche Farma, Sanofi-Aventis, Seagen, Solti, Zymeworks, Pharmalex Spain SLU; Financial Interests, Personal, Expert Testimony: AX's Consulting SARL, Boehringer Ingelheim, Bristol Meyers Squibb, INDITEX, Merck Sharp & Dohme España, Novartis, SACE Medhealth SL, Simon Kucher &Partners SL, Genentech, Innoup, Millenium, Sanofi, Seattle Genetics; Financial Interests, Personal, Other, SC: Byondis B.V., German Breast Group, Glaxo, International Breast Cancer Study Group (IBCSG), Macrogenics, Medsir, Menarini, Merus, Merus, Netherlands Cancer Institute (NKI), Queen Mary (University of London), Seagen, Synthon Biopharpaceuticals; Financial Interests, Institutional, Research Grant: AstraZeneca, Bayer Pharma, Boehringer Ingelheim, Bristol Myers Squibb (BMS), Cytomx Therapeutics, Daiichi Sankyo, Eli Lilly and Company, F. Hoffmann-La Roche Ltd., Genentech, Glaxosmithkline, Immunomedics, Innoup Farma, International Breast Cancer Study Group (IBCSG), Macrogenics, Medica Scientia Innovation Research, Menarini Ricerche, Merus, Novartis, Pfizer, Puma, Roche, Sanofi-Aventis, Seattle Genetics, SOLTI; Financial Interests, Institutional, Invited Speaker: Byondis B.V.; Non-Financial Interests, Member: Spanish Society of Medical Oncology (SEOM), American Society for Clinical Oncology (ASCO), SOLTI group (Academic research group in breast cancer), Geicam (Spanish Breast Cancer Research Group), American Association for Cancer Research (AACR). M. Bellet-Ezquerra: Financial Interests, Personal, Advisory Board: Pfizer, Novartis, Lilly, Stemline-Menarini; Other, Speaker's Bureau and Travel Expenses: Pfizer; Other, Speaker's Bureau: Novartis, Lilly. All other authors have declared no conflicts of interest.