Adjuvant treatment decision in patients with node-negative, ER+/Her2-, early stage breast cancer with Oncotype DX (ODX) recurrence score (RS) of 11-30: Impact of clinicopathologic features.

Abstract

e12022 Background: The ODX RS predicts the risk of distant recurrence and the benefit of adjuvant chemotherapy (CT) in patients with ER+/Her2- breast cancer. High RS predicts a large benefit whereas low RS predicts minimal benefit from CT. A prospective trial showed that patients with low RS of 0-10 may be safely spared adjuvant CT. Recommendations in patients with intermediate RS are less clear. We performed a retrospective study of adjuvant therapy decision in patients with RS 11-30. Methods: We identified patients with ER+/Her2-, node-negative breast cancer with ODX RS 11-30 treated at our center from 2010-2016. Data on patient age, type of surgery, tumor size, grade, lymphovascular invasion (LVI), RS and treatment were collected. Statistical associations were tested using Chi square/Fisher's exact test and t test. Logistic regression analysis was used to determine odds ratios (OR). Results: 76 patients were identified. 86% (65/76) of them received adjuvant endocrine therapy alone and 14% (11/76) received adjuvant CT plus endocrine therapy. Patient characteristics are shown in the table. Using univariate analysis, significant predictors of receiving CT included RS, LVI, and ER positivity. In the patients who received CT, RSs were all ≥ 18 whereas in the group who did not receive CT, 42% (27/65) patients had RS 11-17. Increase in RS was associated with increase in the likelihood of receiving CT (OR 1.40, 95% CI 1.14-1.74, p=0.00017). Decrease in ER positivity was correlated with increased likelihood of receiving CT (OR 0.922, 95% CI 0.856-0.992, p=0.03). The presence of LVI increased the likelihood of receiving CT (OR 26.24, 95% CI 4.16-165.43, p=0.0005). Conclusions: In patients with ER+/Her2-, node-negative breast cancer with RS 11-30, the majority received endocrine therapy alone. RS and some clinicopathologic features (LVI, ER) impacted the decision to receive CT. [Table: see text]