Abstract 181P
Background
Biomarkers of cellular proliferation (eg. Ki67≥20%) may be useful in estimating recurrence risk in HR+, HER2- early breast cancer (EBC: Stage I-III). The use of chemotherapy (CT) depends on multiple factors including the patient’s (pt) estimated risk of recurrence. One area of uncertainty in risk estimation is in pts with 1-3 positive nodes. This study aimed to understand the use of Ki67 testing and scoring in pts with node+, HR+, HER2- EBC and treatment (trt) patterns.
Methods
An observational retrospective cohort study of HR+, HER2- EBC pts treated (JAN2010-AUG2018) in community practices utilized molecular and clinical data aggregated via Genospace, a web-based data analysis platform. Inclusion criteria: pts (>18 yrs) diagnosed with HR+, HER2- invasive EBC. Demographic, pathologic, and trt data were collected. Multivariable logistic regression (MLR) was used to analyze predictors of testing and Ki67 scores≥20%.
Results
555 (98%) of 567 pts (mean age 58y, SD 12.7y) with initial tumor stage I (63), II (370), III (121), unknown (13) received systemic therapy for EBC. 91 (16%) pts received neo-adj therapy. Adj therapy was received by 525 (95%) pts, with 428 (82%) receiving endocrine therapy (ET) in the regimen and 175 (33%) treated with CT followed by ET. Among pts with 1–3 positive nodes (n=258), 24% (61) were tested for Ki67 expression. Of these, 54% (33/61) had scores of ≥20%. Following Ki67 testing, 59% pts had CT and 67% pts with Ki67≥20% received CT. MLR analyses showed that clinical or pathological factors were not predictors of Ki67 testing. Individuals without insurance were less likely to receive Ki67 testing (HR -2.7, p<0.0003). Of those tested (n=130), grade 2 (p=0.0027) and grade 3 (p<0.001) were predictors of Ki67 scores ≥20%. Overall, Ki67≥20% was common among those with grade 2 (64%) or grade 3 (94%) tumors, however, 28% of pts with grade 1 tumors also had Ki67≥20%.
Conclusions
HR+ EBCs are routinely treated with ET+/-CT. Markers of cellular proliferation, such as Ki67, are prognostic of risk of recurrence. Clinical and pathological factors were not predictors of Ki67 testing. Higher Ki67 scores were not limited to high grade tumors. The role of high Ki67 in general, and in lower grade tumors, remains unclear.
Clinical trial identification
Editorial acknowledgement
Trish Huynh (Eli Lilly and Company, Indianapolis, IN) provided writing assistance.
Legal entity responsible for the study
Eli Lilly and Company.
Funding
Eli Lilly and Company.
Disclosure
J. Brown: Shareholder/Stockholder/Stock options, Full/Part-time employment: Eli Lilly and Company. S. Scardo: Full/Part-time employment: Eli Lilly and Company. M. Method: Shareholder/Stockholder/Stock options, Full/Part-time employment: Eli Lilly and Company. E.P. Hamilton: Advisory/Consultancy, Research grant/Funding (institution), Non-remunerated activity/ies, Non-financial support - payment or reimbursement of exact amount of expenses: Eli Lilly and Company; Advisory/Consultancy, Research grant/Funding (institution): Pfizer; Advisory/Consultancy, Research grant/Funding (institution), Non-financial support - payment or reimbursement of exact amount of expenses: Genentech/Roche; Advisory/Consultancy, Research grant/Funding (institution): Puma Biotechnology; Advisory/Consultancy, Research grant/Funding (institution), Non-financial support - payment or reimbursement of exact amount of expenses: Daiichi Sankyo; Advisory/Consultancy, Research grant/Funding (institution): Mersana; Advisory/Consultancy, Research grant/Funding (institution): Boehringer Ingelheim; Advisory/Consultancy, Research grant/Funding (institution): Cascadian Therapeutics; Advisory/Consultancy, Research grant/Funding (institution), Non-financial support - payment or reimbursement of exact amount of expenses: AstraZeneca; Research grant/Funding (institution): Hutchinson MediPharma; Research grant/Funding (institution): OncoMed; Research grant/Funding (institution): MedImmune; Research grant/Funding (institution): Stem CentRx; Research grant/Funding (institution): Curis; Research grant/Funding (institution): Verastem; Research grant/Funding (institution): Zymeworks; Research grant/Funding (institution): Syndax; Research grant/Funding (institution): Lycera; Research grant/Funding (institution): Rgenix; Research grant/Funding (institution): Millennium; Research grant/Funding (institution): TapImmune; Research grant/Funding (institution): BerGenBio; Research grant/Funding (institution): MedIvation; Research grant/Funding (institution), Non-financial support - payment or reimbursement of exact amount of expenses: Tesaro; Advisory/Consultancy, Research grant/Funding (institution), Non-financial support - payment or reimbursement of exact amount of expenses: Eisai; Research grant/Funding (institution): H3 Biomedicine; Honoraria (institution), Non-financial support - payment or reimbursement of exact amount of expenses: Radius Health; Research grant/Funding (institution): Acerta Pharma; Research grant/Funding (institution): Takeda; Research grant/Funding (institution): Macrogenics; Research grant/Funding (institution): AbbVie; Research grant/Funding (institution): Immunomedics; Research grant/Funding (institution): Fujifilm; Research grant/Funding (institution): eFFECTOR Therapeutics; Research grant/Funding (institution): Merus; Research grant/Funding (institution): Nucana; Research grant/Funding (institution): Regeneron; Research grant/Funding (institution): Leap Therapeutics; Research grant/Funding (institution): Talho Pharmaceutical; Research grant/Funding (institution), Non-remunerated activity/ies, Non-financial support - Payment or reimbursement of exact amount of expenses: EMD Serono; Research grant/Funding (institution): Syros; Research grant/Funding (institution), Non-remunerated activity/ies, Non-financial support - Payment or reimbursement of exact amount of expenses: Clovis; Research grant/Funding (institution): CytomX; Research grant/Funding (institution): InventisBio; Non-remunerated activity/ies, Payment or reimbursement of exact amount of expenses: Amgen; Non-remunerated activity/ies, Payment or reimbursement of exact amount of expenses: Bayer; Non-remunerated activity/ies, Payment or reimbursement of exact amount of expenses: Bristol-Myers Squibb; Non-remunerated activity/ies, Payment or reimbursement of exact amount of expenses: Genzyme; Non-remunerated activity/ies, Payment or reimbursement of exact amount of expenses: Helsinn Therapeutics; Non-remunerated activity/ies, Payment or reimbursement of exact amount of expenses: HERON; Non-remunerated activity/ies, Payment or reimbursement of exact amount of expenses: Lexicon; Non-remunerated activity/ies, Payment or reimbursement of exact amount of expenses: Medivation; Non-remunerated activity/ies, Payment or reimbursement of exact amount of expenses: Merck; Advisory/Consultancy, Research grant/Funding (institution), Non-remunerated activity/ies, Payment or reimbursement of exact amount of expenses: Novartis; Non-remunerated activity/ies, Payment or reimbursement of exact amount of expenses: Roche; Non-remunerated activity/ies, Payment or reimbursement of exact amount of expenses: Sysmex; Non-remunerated activity/ies, Payment or reimbursement of exact amount of expenses: Guardant Health; Non-remunerated activity/ies, Payment or reimbursement of exact amount of expenses: Foundation Medicine; Research grant/Funding (institution): Deciphera; Advisory/Consultancy, Research grant/Funding (institution): Silverback; Advisory/Consultancy, Research grant/Funding (institution): Black Diamond; Research grant/Funding (institution): ArQule; Research grant/Funding (institution): Sermonix Pharmaceuticals; Research grant/Funding (institution): Sutro Biopharma; Research grant/Funding (institution): Zenith Epigenetics; Research grant/Funding (institution): Arvinas; Research grant/Funding (institution): Torque Therapeutics; Research grant/Funding (institution): Harpoon Therapeutics; Research grant/Funding (institution): Fonchon Pharmaceuticals; Research grant/Funding (institution): Orinove; Research grant/Funding (institution): Molecular Templates; Research grant/Funding (institution): Unum Therapeutics; Research grant/Funding (institution): Aravive; Advisory/Consultancy: NanoString; Research grant/Funding (institution): Compugen; Research grant/Funding (institution): Dana Farber Cancer Institute; Research grant/Funding (institution): G1 Therapeutics; Research grant/Funding (institution): Karyopharm Therapeutics; Research grant/Funding (institution): Torque Therapeutics. S. Jones: Research grant/Funding (institution): Eli Lilly and Company. H. Burris: Research grant/Funding (institution): Eli Lilly and Company; Research grant/Funding (institution): Aglos; Advisory/Consultancy, Research grant/Funding (institution): AstraZeneca; Research grant/Funding (institution): Arch; Research grant/Funding (institution): Array BioPharma; Research grant/Funding (institution): Arvinas; Research grant/Funding (institution): Bayer; Research grant/Funding (institution): BIND Therapeutics; Research grant/Funding (institution): BioAtla; Research grant/Funding (institution): BioMed Valley; Research grant/Funding (institution): Boehringer Ingelheim; Research grant/Funding (institution): Bristol Myers Squibb; Research grant/Funding (institution): CicloMed; Research grant/Funding (institution): CytomX; Research grant/Funding (institution): eFFECTOR; Research grant/Funding (institution): Roche/Genentech; Research grant/Funding (institution): Gilead Sciences; Research grant/Funding (institution): Harpoon Therapeutics; Advisory/Consultancy, Research grant/Funding (institution): Incyte; Research grant/Funding (institution): Janssen; Honoraria (institution): Jounce Therapeutics; Honoraria (institution): Kymab; Honoraria (institution): MacroGenics; Honoraria (institution): MedImmune; Research grant/Funding (institution): Merck; Research grant/Funding (institution): Millennium Pharmaceuticals; Research grant/Funding (institution): Mirna Therapeutics; Research grant/Funding (institution): Moderna; Research grant/Funding (institution): Novartis; Advisory/Consultancy, Research grant/Funding (institution), Non-compensated consulting: Pfizer; Research grant/Funding (institution): Revolution Medicine; Research grant/Funding (institution): Seattle Genetics; Research grant/Funding (institution): Tesaro; Research grant/Funding (institution): TG Therapeutics; Research grant/Funding (institution): Verastem; Research grant/Funding (institution): Vertex Pharmaceutical; Advisory/Consultancy: Celgene; Advisory/Consultancy: Daiichi Sankyo; Advisory/Consultancy: FORMA Therapeutics; Leadership role, Shareholder/Stockholder/Stock options: HCA/Sarah Cannon. D.R. Spigel: Advisory/Consultancy, Research grant/Funding (institution), Travel/Accommodation/Expenses: Eli Lilly and Company; Advisory/Consultancy, Research grant/Funding (institution): Genentech/Roche; Advisory/Consultancy, Research grant/Funding (institution): Novartis; Advisory/Consultancy, Research grant/Funding (institution): Celgene; Advisory/Consultancy, Research grant/Funding (institution): Bristol-Myers Squibb; Advisory/Consultancy, Research grant/Funding (institution): AstraZeneca; Advisory/Consultancy, Research grant/Funding (institution): Pfizer; Advisory/Consultancy, Research grant/Funding (institution): Boehringer Ingelheim; Advisory/Consultancy, Research grant/Funding (institution): AbbVie; Advisory/Consultancy, Research grant/Funding (institution): Foundation Medicine; Advisory/Consultancy, Research grant/Funding (institution): GlaxoSmithKline; Advisory/Consultancy, Research grant/Funding (institution): Merck; Advisory/Consultancy: Moderna Therapeutics; Advisory/Consultancy, Research grant/Funding (institution): Nektar; Advisory/Consultancy, Research grant/Funding (institution): Takeda; Advisory/Consultancy, Research grant/Funding (institution): Amgen; Advisory/Consultancy: TRM Oncology; Advisory/Consultancy: Precision Oncology; Advisory/Consultancy: Evelo Therapeutics; Advisory/Consultancy: Illumina; Advisory/Consultancy: PharmaMar; Research grant/Funding (institution): University of Texas Southwestern Medical Center - Simmons Cancer Center; Research grant/Funding (institution): G1 Therapeutics; Research grant/Funding (institution): Neon Therapeutics; Research grant/Funding (institution): Celldex; Research grant/Funding (institution): Clovis Oncology; Research grant/Funding (institution): Daiichi Sankyo; Research grant/Funding (institution): EMD Serono; Research grant/Funding (institution): Astellas Pharma; Research grant/Funding (institution): GRAIL; Research grant/Funding (institution): Transgene; Research grant/Funding (institution): Aeglea Biotherapeutics; Research grant/Funding (institution): Tesaro; Research grant/Funding (institution): Ipsen; Advisory/Consultancy: Aptitude Health; Advisory/Consultancy: Bayer; Advisory/Consultancy: Dracen Pharmaceuticals; Advisory/Consultancy: Iksuda Therapeutics; Advisory/Consultancy: Molecular Templates; Advisory/Consultancy: Seattle Genetics; Advisory/Consultancy: TRIPTYCH Health Partners; Research grant/Funding (institution): Janssen; Research grant/Funding (institution): MedImmune; Research grant/Funding (institution): BIND Therapeutics; Research grant/Funding (institution): Eisai; Research grant/Funding (institution): ImClone Systems; Advisory/Consultancy: Intellisphere. All other authors have declared no conflicts of interest.