{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,19]],"date-time":"2026-06-19T18:53:52Z","timestamp":1781895232798,"version":"3.54.5"},"reference-count":23,"publisher":"Oxford University Press (OUP)","issue":"7","license":[{"start":{"date-parts":[[2026,5,15]],"date-time":"2026-05-15T00:00:00Z","timestamp":1778803200000},"content-version":"vor","delay-in-days":1,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Natural Sciences and Engineering Research Council of Canada (NSERC) Vanier Canada Graduate Scholarship","award":["198875"],"award-info":[{"award-number":["198875"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"published-print":{"date-parts":[[2026,6,6]]},"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>Ki-67 is widely used in breast cancer; however, the fraction of patients in whom it meaningfully alters treatment decisions is not well established. Using a guideline-based approach anchored in National Comprehensive Cancer Network (NCCN) recommendations (v2.2026), we identified clinical scenarios in which Ki-67 directly modifies adjuvant therapy decisions and estimated their prevalence using population-level data and complementary datasets, recognizing that fully annotated datasets capturing all relevant clinicopathological variables remain limited. A back-of-the-envelope calculation suggests that only a small fraction of patients meet the combined criteria of HR+\/HER2\u2212 subtype, T2 stage, grade 2 histology, and Ki-67\u2009\u2265\u200920%. This estimate, compared to population-scale (n\u2009=\u2009117\u2009990 patients) and curated datasets (n\u2009=\u20091356 patients), indicates that the clinically relevant subset remains in the low single digits (3-5%). Ki-67 impacts care only in specific decision settings, particularly near clinically relevant thresholds where small analytic variation may translate into treatment changes; outside these contexts, its routine use has limited evidence for clinical utility. Its application should therefore be selective, context-dependent, and focused on scenarios in which threshold-adjacent precision is clinically consequential.<\/jats:p>","DOI":"10.1093\/oncolo\/oyag183","type":"journal-article","created":{"date-parts":[[2026,5,11]],"date-time":"2026-05-11T11:20:20Z","timestamp":1778498420000},"source":"Crossref","is-referenced-by-count":0,"title":["Ki-67 as a treatment decision modifier in breast cancer"],"prefix":"10.1093","volume":"31","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-7668-9356","authenticated-orcid":false,"given":"Amanda","family":"Dy","sequence":"first","affiliation":[{"name":"Electrical, Computer, and Biomedical Engineering, Toronto Metropolitan University , Toronto, ON M5B 2K3,","place":["Canada"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2434-4978","authenticated-orcid":false,"given":"Jochen K","family":"Lennerz","sequence":"additional","affiliation":[{"name":"Natera Pathology Innovations, , Austin, TX 78753,","place":["United States"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"286","published-online":{"date-parts":[[2026,5,14]]},"reference":[{"key":"2026061914101694700_oyag183-B1","doi-asserted-by":"publisher","first-page":"1080","DOI":"10.1056\/NEJMoa2305488","article-title":"Ribociclib plus endocrine therapy in early breast cancer","volume":"390","author":"Slamon","year":"2024","journal-title":"N Engl J Med"},{"key":"2026061914101694700_oyag183-B2","author":"Jarosek S, Tuttle TM, Durham S","year":"2012"},{"key":"2026061914101694700_oyag183-B3","author":"Seer","year":"2025"},{"key":"2026061914101694700_oyag183-B4","doi-asserted-by":"publisher","first-page":"105552","DOI":"10.1016\/j.esmoop.2025.105552","article-title":"Endocrine response assessment in HR-positive HER2-negative early breast cancer: concordance of local versus Central Ki67 measurements in the WSG ADAPTcycle trial (n = 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high-risk early breast cancer (monarchE): results from a preplanned interim analysis of a randomised, open-label, phase 3 trial","volume":"24","author":"Johnston","year":"2023","journal-title":"Lancet Oncol"},{"key":"2026061914101694700_oyag183-B8","author":"Tandon","year":"2023"},{"key":"2026061914101694700_oyag183-B9","doi-asserted-by":"publisher","first-page":"1244","DOI":"10.1038\/s41379-019-0270-4","article-title":"Combined quantitative measures of ER, PR, HER2, and KI67 provide more prognostic information than categorical combinations in luminal breast cancer","volume":"32","author":"Abubakar","year":"2019","journal-title":"Mod Pathol"},{"key":"2026061914101694700_oyag183-B10","doi-asserted-by":"publisher","first-page":"2","DOI":"10.1038\/s41523-023-00605-3","article-title":"Qualification of a multiplexed tissue imaging assay and detection of novel patterns of HER2 heterogeneity in breast cancer","volume":"10","author":"Guerriero","year":"2024","journal-title":"NPJ Breast 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cancer","volume":"16","author":"O\u2019Keefe","year":"2024","journal-title":"Breast Cancer (Dove Med Press)"},{"key":"2026061914101694700_oyag183-B19","doi-asserted-by":"publisher","first-page":"129","DOI":"10.4132\/jptm.2015.12.24","article-title":"Interobserver variability of Ki-67 measurement in breast cancer","volume":"50","author":"Chung","year":"2016","journal-title":"J Pathol Transl Med"},{"key":"2026061914101694700_oyag183-B20","doi-asserted-by":"publisher","first-page":"219","DOI":"10.1016\/j.ejca.2017.07.041","article-title":"Interlaboratory variability of Ki67 staining in breast cancer","volume":"84","author":"Focke","year":"2017","journal-title":"Eur J Cancer"},{"key":"2026061914101694700_oyag183-B21","doi-asserted-by":"publisher","first-page":"59","DOI":"10.1038\/s41379-018-0109-4","article-title":"An international multicenter study to evaluate reproducibility of automated scoring for assessment of Ki67 in breast 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