Abstract PO2-02-03: Clinical and pathological factors associated with Oncotype DX® 21-Gene recurrence score in patients diagnosed with early stage breast cancer in a low-middle income country

Abstract INTRODUCTION: Oncotype DX® recurrence score (ODX RS) is a 21-gene assay warranted to determine the the prognosis in patients with hormone receptor positive, HER-2 negative early stage breast cancer. In this context, the test is also predictive of benefit of adjuvant chemotherapy.1,2,3 OBJECTIVES: We aimed to correlate the clinical and pathological factors associated with Oncotype DX® 21-Gene in patients diagnosed with early stage Breast Cancer. Additionally, description of adjuvant treatment patterns and survival outcomes were described according to the Oncotype DX® 21-Gene result. METHODS: Data from medical records from a single center in Brazil were collected retrospectively from women over 18 years diagnosed with early breast cancer between 2012 and 2022. Included patients were diagnosed with stage T1-T2 breast cancer, hormone receptor positive, HER-2 negative, with up to three positive lymph nodes. All included patients had an Oncotype DX® test performed after definitive breast surgery. The ODX RS has been categorized into two levels according to menopausal status. Correlation between breast cancer recurrence and clinicopathological characteristics was done. The software SPSS was used for statistical analyzes with the significance of 0.05. RESULTS: From 197 patients, 20 have had breast cancer recurrence (10.15%) whom 10 were premenopausal and 10 were postmenopausal. The median ODX RS in these 20 patients was 15 (ranged from 9 to 31). The most common site of recurrence was breast and regional recurrence in 18 patients (90%). Adjuvant chemotherapy was omitted in 16 patients (80%) who have had breast cancer recurrence. Among premenopausal patients whose ODX RS was 20, 33 patients (91.66%) received adjuvant chemotherapy. Among postmenopausal patients whose ODX RS was 25, 19 (86.36%) received adjuvant chemotherapy. The probability of recurrence free survival was worse in premenopausal patients 44-years-old compared to those with =44 years-old (p = 0.036) and also worse in histological grade 3 tumors compared to grade 1 (p=0.0048). Tumor size 14 millimeters (mm) was correlated to worse recurrence free survival in premenopausal patients (p=0.017). Low estrogen and progesterone receptor was associated with a higher ODX RS (p=0.0035 and p 0.0001, respectively) in premenopausal patients, but not associated with recurrence free survival. Clinicopathological characteristics and recurrence free survival correlation in postmenopausal patients were not significant. CONCLUSION: This retrospective analysis suggests that factors other than the Oncotype DX® score, such as age and grade contributed to worse survival outcomes among our patients population. Of note, age older than 44 years-old, histological grade 3 and tumor size 14 mm were associated with a higher probability of recurrence in premenopausal patients, despite the Oncotype DX® score. REFERENCES: 1. Paik S, Shak S, Tang G, Kim C, Baker J, Cronin M, et al. A multigene assay to predict recurrence of tamoxifen-treated, node-negative breast cancer. N Engl J Med Internet. 2004;351(27):2817–26. Available from: http://dx.doi.org/10.1056/NEJMoa041588. 2. Sparano JA, Gray RJ, Makower DF, Pritchard KI, Albain KS, Hayes DF, et al. Adjuvant chemotherapy guided by a 21-gene expression assay in breast cancer. N Engl J Med Internet. 2018;379(2):111–21. Available from: http://dx.doi.org/10.1056/NEJMoa1804710. 3. Kalinsky K, Barlow WE, Gralow JR, Meric-Bernstam F, Albain KS, Hayes DF, et al. 21-gene assay to inform chemotherapy benefit in node-positive breast cancer. N Engl J Med Internet. 2021;385(25):2336–47. Available from: http://dx.doi.org/10.1056/NEJMoa2108873. Table 1 – Clinical and pathological characteristics of 197 hormone receptor positive, HER-2 negative early breast cancer patients who did the Oncotype DX® 21-Gene Recurrence Score assay. Data from medical records collected retrospectively of women diagnosed with early breast cancer between 2012 and 2022 from a single center in Brazil. Figure 1 – Probability of recurrence free survival in premenopausal patients according to age =44 (blue line) or 44-years-old (pink line). Data from medical records collected retrospectively of women with hormone receptor positive, HER-2 negative early breast cancer who did the Oncotype DX® 21-gene assay diagnosed between 2012 and 2022 from a single center in Brazil. Figure 2 – Probability of recurrence free survival in premenopausal patients according to histological grade. Tumor with histological grade 1 (blue line) or histological grade 3 (pink line). Data from medical records collected retrospectively of women with hormone receptor positive, HER-2 negative early breast cancer who did the Oncotype DX® 21-gene assay diagnosed between 2012 and 2022 from a single center in Brazil. Citation Format: Carolina Cavalcanti Gonçalves Ferreira, Julio Araujo, Shermann Brandão Rodrigues Moreira, Antônio Buzaid, Débora Gagliato. Clinical and pathological factors associated with Oncotype DX® 21-Gene recurrence score in patients diagnosed with early stage breast cancer in a low-middle income country abstract. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO2-02-03.