Intermediate Oncotype DX Scores Prognostic of OS in Early-stage Breast Cancer

Intermediate-range Oncotype DX recurrence scores (RS) have prognostic value for overall survival (OS) among women with early-stage hormone receptor-positive (HR+) breast cancer, according to study results to be presented at the 2017 San Antonio Breast Cancer Symposium.

Oncotype DX is a tumor profiling test that analyzes a tumor sample for a group of 21 genes to determine the risk stratification for patients in whom chemotherapy may be beneficial. High or low Oncotype DX RS have demonstrated usefulness in guiding treatment decisions, but the utility of an intermediate RS has not been elucidated.

For this retrospective study, outcomes data of 24,945 women with early-stage, HR+ breast cancer who had Oncotype DX RS in the intermediate range (18 to 30) were analyzed. Researchers assessed the association between intermediate RS and overall survival among patients who received chemotherapy using Cox proportional hazard models, adjusting for patient characteristics such as age, race/ethnicity, year of diagnosis, and tumor size.

Of the 24,945 study patients, 10,129 (41.4%) received chemotherapy depending on their RS scores, ranging from 19.1% and 76.1% of patients with RS scores of 19 and 30, respectively.

The results showed that patients who received chemotherapy had a significant reduction in the risk of death (hazard ratio [HR], 0.77; 95% CI, 0.62-0.96, P =.02), and furthermore demonstrated that higher RS scores correlated with an increased risk of death; a 1-point increase in RS score resulted in a 6.2% increase in mortality risk (95% CI, 3.2%-9.2%; P <.0001).

Patients with an RS of 27 to 30 had a 1.64-fold increased risk of death (95% CI, 1.13-2.37), compared with patients who were in the lower-intermediate RS range of 18 to 20.

Oncotype DX RS scores and overall survival were more strongly associated in women younger than 50 years, with a HR per 1 unit increment of 1.28 (95% CI, 1.17-1.40) compared with 1.04 (95% CI, 1.01-1.07) in women 50 years and older.

The authors concluded, “As we eagerly await results from randomized clinical trials, young women with intermediate RS should be counseled to consider more aggressive treatment including chemotherapy, ovarian function suppression, or participation in ongoing clinical trials of CDK inhibitors to improve overall survival outcomes.”

Reference

Ibraheem AF, Press D, Dezheng H, Olopade F. Clinical practice and mortality in patients with oncotype DX intermediate score: what do we know about the gray zone? Poster presentation at: 2017 San Antonio Breast Cancer Symposium (SABCS); December 5-9, 2017; San Antonio, TX.