e12520 Background: Oncotype Dx (ODX) is a commercial diagnostic test primarily used to predict the likely benefit from chemotherapy in ER+, HER2-, and node negative breast cancer. The prognostic value (recurrence risk) has also been demonstrated to apply to early stage lymph node positive (LN+) disease in a number of retrospective and prospective studies. The ongoing RxPONDER trial aims to clarify the predictive value of RS in LN+ population. In light of the initial results, we analyzed the practice patterns and outcomes for HR+/Her2 -/node positive breast cancer patients receiving ODX testing in the years from 2010-2017 with RS 14-25 in a retrospective observational study of the NCDB. Methods: Women with HR+/Her2 -/node positive breast cancer receiving ODX testing from 2010-2017 were identified in the NCDB using TAILORx and RxPONDER patients’ inclusion criteria: ages 18-75, 6-50mm invasive tumors, N1, M0, ER+/HER2 -. The impact of ODX results in the high-intermediate range (14-25) and other clinico-pathologic variables on the receipt of chemotherapy were compared. Additionally, we examined the impact of chemotherapy on overall survival (OS). Frequencies, Kaplain-Meier analysis, and changepoint analysis using the Contal and O’Quigley method were utilized. Results: There were 109,652 T1-2 and N1 patients of whom 32,506 (29.6%) received ODX testing. 13,461 (41.4%%) women had scores in the high-intermediate (14-25) range. The majority tended to have only 1 LN involved (1LN: 77.2%, 2LNs: 17.5%, 3LNs: 5.3%), had a mean age of 57.8y, were Caucasian (86.4%), and were preferentially tested at academic or comprehensive community cancer programs (79.2%). 6,610 (49.3%) patients were recommended chemotherapy, the median ODX score for all women who were recommended chemotherapy was 20 compared to 17 for those whom chemotherapy was not recommended. 5,068 (76.7%) women had documentation of receiving chemotherapy which correlated with improved OS regardless of age. Conclusions: In the group of women with HR+/Her2 -/node positive breast cancer, clinicians appear to utilize ODX testing in less than one-third of patients, possibly finding RS to be most useful in guiding adjuvant therapy recommendations when only 1LN is involved. Both the recommendation and receipt of chemotherapy correlated linearly with increasing RS, as expected based on the current NCCN guideline recommendations. We identified an OS benefit when chemotherapy was administered, regardless of patient age. Long-term follow-up in the RxPONDER trial will likely continue to clarify the predictive value of RS < 25 in the ER+/HER2-/node positive breast cancer population.
p53 Expression in Node-Positive Breast Cancer Patients: Results from the Cancer and Leukemia Group B 9344 Trial (159905)
