P5-14-26: Results from a Prospective Clinical Study on the Impact of Oncotype DX on Adjuvant Treatment Decision Making in a Cohort of 142 UK Patients.

Abstract

Abstract Objectives: International guidelines support the use of the Oncotype DX derived Recurrence Score (RS) to provide additional prognostic and predictive information in early breast cancer but experience in the UK is limited. In our prospective study we evaluate this test for the NHS and its impact on costs (subject of a separate abstract) and treatment recommendations by UK oncologists. Methods: 150 tests were made available to consecutive patients with ER+, pN0, pN1itc or pN1mic early breast cancer who had no contraindication to adjuvant chemotherapy (CT) and who would accept CT + hormone therapy (HT) if recommended. CT recommendations of oncologists based on Adjuvant! Online figures were recorded at an initial consultation. Eligible patients were consented to Oncotype DX testing and review arranged once the result was available. After a second consultation a final decision on adjuvant therapy was recorded. Results: Analysis is based on 142 patients. (150 tests performed, 3 failed to give a result, 3 repeated tests giving a result on the second block, one bilateral and one test stopped because the patient withdrew from the study). Initial treatment recommendations changed in 38 (26.8%) cases. Of the patients initially recommended CT + HT (total 57 patients), 26 (45.6%) patients were spared chemotherapy after review with the RS. Of the 85 patients initially recommended HT only 12 (14.1%) were changed to HT + CT. Further analysis shows that Grade, estrogen receptor status by immunohistochemistry (ER by IHC) and progesterone receptor by immunohistochemistry (PR by IHC) are correlated to RS but in our cohort age, size and node status were not. (Spearman rank correlation for grade is 0.05, 95%, Cl 0.36 to 0.61; for ER by IHC is −0.36, Cl −0.49 to −0.20; and for PR by IHC is −0.49, 95%, Cl −0.60 to −0.35). Apart from HER2 positive patients who are already recognized to return a high RS, further analysis of our series shows no clear combination of currently available prognostic factors that would predict RS and therefore reliably avoid testing of any subset of patients. Conclusion: The results of our study suggest that Oncotype DX is applicable and feasible to perform in UK patients with a reduction in the use of adjuvant chemotherapy consistent with findings of reported studies. RS added prognostic information beyond information provided by Adjuvant! Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P5-14-26.