Abstract P6-06-46: Treatment decisions and five year outcomes of the oncotype Dx test: An independent assessment

Abstract

Abstract INTRODUCTION: Oncotype DX (ODx) was validated to provide prognostic information in ER+ lymph node negative tumors. The work of Paik et al. (JCO 2006 23:3737) has provided evidence of predictive power of ODx for chemotherapy, but there is contrary literature in this regard (Ionnadis JP Oncologist 2007, 12: 301-11; NICE Guideline March 2013 http://guidance.nice.org.uk/DT4). The specific aims of our institutional study are to determine (1) how ODx influenced treatment decisions and (2) the outcomes of patients who had ODx. METHODS: Tumor registry follow-up information was supplied for 580 patients who had ODx and follow-up (mean/median 60/63 months). RESULTS: (Table 1) Distribution of RS was 40% intermediate (232/580), 15% high RS (87/580) and 45% (261/580) low RS. Hormonal therapy was recommended to 96% (558 of 580), but refused by 3% (16 of 580) and for 1% data was unavailable. In the high RS group, chemo was recommended to 90% (79 of 87), of which 6 (8%) refused. In the intermediate RS group, chemo was recommended to 49% of the patients of which 20 (18% of recommended) refused. In the low RS group, chemo was recommended to 12% of the patients of which 8 (26% of recommended) refused. Most chemotherapy treatment decisions made at our institution were based on oncotype DX. High RS group recurrence was 9% (7 of 87) of which 2 patients died. Of these 7 patients, 3 did not receive chemotherapy (2 were recommended but refused). The recurrence rate in the intermediate RS group was 6.5% (14 of 232) of which 3 patients died. Of these 14 patients, 8 did not receive chemotherapy based on clinician's judgment. The recurrence rate in the low RS group was 1% (3 of 261) and there were no deaths due to breast cancer. Of these 3 cases, one received chemotherapy. Oncotype DX Type of Recurrence vs Recurrence ScoresType RecurrenceHigh RSIntermediate RSLow RSTotalLocoregional49114(Scores)(35,38,47,63)(19,20,20,23,24,26,26,27,29)(16) Distant2529(Scores)(31,61)(19,19,22,29,30)(2,11) Local or Distant1 1Total714324 Conclusion: (1) The oncotype DX recurrence score is prognostic when low risk and high risk categories are considered. (2)The large number (40%) of intermediate RS appears to be a prognostic limitation of the test. (3) Of patients that recurred, (50%) received chemotherapy and were somewhat equally distributed between the high RS and the intermediate RS categories. Further follow-up of this cohort should address concerns of clinical utility of the Oncotype Dx test, especially for the intermediate RS category. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-06-46.