A retrospective look at node-negative, hormone receptor-positive HER2-negative breast cancers ≤1 cm treated with breast conservation between 2008-2020 at MSKCC compared outcomes for those with high Oncotype DX recurrence scores (≥26; n=231) against similarly small tumors with scores <26 (n=1,747). In-line with guidelines, those with high-risk genomic scores received substantially more chemotherapy (74% vs 9%) yet outcomes remained significantly worse. Rates of locoregional recurrence-free survival was 94% versus 99%, respectively, at 5 years and 88% versus 96% at 10 years. On multivariable analysis accounting for things like lymphovascular invasion, grade 3 disease, and positive margins, high-risk genomic scores continued to independently predict locoregional recurrence (HR 2.9). The authors conclude a high-risk genomic score should give pause to any consideration of radiation omission and even partial breast irradiation. | Khan, Int J Radiat Oncol Biol Phys 2026
