Impact of oncotype Dx score on treatment and long-term outcomes.

Abstract

e12518 Background: Oncotype dx is a 21 gene breast cancer assay that helps predict benefit of chemotherapy in early-stage hormone receptor positive (HR+), HER2 negative, 0 to 3 node positive breast cancer as reported by TAILORx and RxPonder trials. Both trials found no benefit of adjuvant therapy in mid-range scores of 11-25 with the exception of some benefit in age under 50 or premenopausal status, no benefit if score was 0-10, and benefit of chemotherapy if >25. Methods: All breast cancer patients between 2019-2020 were chart checked to evaluate oncotype dx scores. Patient characteristics were analyzed between oncotype dx scores of 0-10, 11-25, and >25 using X square tests. 2000-2020 institutional cancer registry data was analyzed to understand recurrence and mortality in patients with oncotype dx testing. Results: 173 patients had oncotype dx testing between 2019-2020, and most were HR+, HER2-, and had 0-3 lymph nodes. There was no difference in race or ethnicity between the groups of oncotype dx scores (Table), and average age at diagnosis for all three groups was 58 years. More patients with lower oncotype dx score had hormone therapy, but this was not significant (0-10 at 93.6%, 11-25 at 90.8%, and >25 at 82.1%, p=0.26). Patients with a higher oncotype score were significantly more likely to have chemotherapy (0-10 at 0%, 11-25 at 17.3%, and >25 at 82.1%, p<0.01). When looking at long term outcomes, the mortality rate was highest in the 11-25 score group at 9.5%, but was not significantly higher than 0-10 at 4.7% and >25 at 2.1% (p=0.15). The recurrence was highest in the 0-10 group at 5.4%, but not significant compared to the 11-25 group at 4.1% and >25 group at 4.2% (p=0.09). Conclusions: Race, ethnicity, and age does not impact predisposition to high oncotype dx score, which is interesting since literature shows minority women have higher mortality rates. This could be because oncotype dx looks at early-stage breast cancers and many minority women have later stages at diagnosis. There was no difference in which group received hormone therapy and there was significantly higher rate of chemotherapy administration in patients with scores >25, which is consistent with prospective trial recommendations. When evaluating long term outcomes between oncotype dx groups over 20 years, there was no significant difference in recurrence of disease or mortality indicating that oncotype dx scoring accurately predicted overall benefit of chemotherapy.[Table: see text]