Treatment pattern of early-stage premenopausal breast cancer patients with low Oncotype DX score: Single center experience.

Abstract

e12510 Background: The predictive value of Oncotype DX in early-stage node negative breast cancer had been previously well established. As per TAILORx, patients with a low Oncotype DX Recurrence Score RS (0–25) did not benefit from chemotherapy. Premenopausal patients are a crucial subgroup for which recommendations based on Oncotype DX are imprecise. Those with Oncotype DX RS 16-25 are thought to have a small benefit from chemotherapy. Our goal was to study the treatment pattern for this group of patients managed at our institution. Methods: We conducted a retrospective analysis to assess premenopausal patients with early-stage breast cancer who had Oncotype DX testing done. All eligible patients were compared based on whether chemotherapy was given or not. The primary endpoint evaluated was the rate of local recurrence. Univariate comparisons were assessed using t-tests or ANOVA for continuous variable & chi-square for categorical variable. Results: A total of 506 patients younger than 50 years diagnosed between 01/2018 and 12/2020 who had an Oncotype DX available were identified. Of these, 344 were White, 137 were Black and 23 identified as another race. The average age of patients was 42.7 ± 5.5 years. Patients treated with chemotherapy were found to be on average younger than those who did not receive chemotherapy (42 years old vs 43.6 years old, P < 0.0001). The average tumor size for patients who got chemotherapy was 3.26 cm compared to an average size of 2.78 cm for patients who avoided chemotherapy. 72.1% of patients with stage 2 disease had received chemotherapy compared to 38.1 % of patient with stage 1. There were 462 patients with RS < 16, 28 patients with RS 16-25, and 16 patients with RS > 25 as illustrated. Patients were followed from a range of 1.8 months to 30.7 months. There were 6 patients who had local recurrences identified, all of which had RS scores < 16. Conclusions: In our study, 91.3% had RS < 16 and generally should have avoided chemotherapy, however 35% of these patients continued to receive chemotherapy. Only 5.5% of our population had RS 16-25, a quarter of which (n = 7) received chemotherapy. Of those 7 patients, 3 had positive lymph node disease. None of these patients had disease recurrence to date. Patients with RS >25 made up 3.2% of the population and would generally benefit from chemotherapy, however 12.5% of these patients did not end up receiving it. Using Oncotype DX in early-stage breast cancer helps avoid chemotherapy safely in majority of patients. [Table: see text]