Lymphovascular invasion in hormone-positive, human epidermal growth factor-negative, low-burden axillary disease in early breast cancer patients tested for oncotype DX recurrence score.

Introduction: The oncotype DX recurrence score (ODX-RS) is a validated 21-gene assay that can quantify the recurrence risk and assess the likelihood of adjuvant chemotherapy benefit in breast cancer. The presence of lymphovascular invasion (LVI) in breast cancer patients is regarded as a predictor for worse prognosis. This study sought to explore the association of ODX-RS with LVI in oestrogen receptor-positive, human epidermal growth factor receptor-2-negative, low-burden nodal disease, early breast cancer. Material and methods: After clinical improvement unit approval, an institutional database was queried to identify the breast cancer cases diagnosed in the period between 2017-2021 that fulfilled the inclusion criteria. The total resected tumours comprised 107 in 102 patients (5 patients had bilateral disease). The data related to patients' age and tumour grade, LVI detection, nodal status, and ODX-RS were analysed. Results: Lymphovascular invasion was identified in 32.6% of 107 tumours. In the age group > 50 years, 13 tumours had lymphovascular invasion (LVI +ve), 9 tumours had ODX-RS < 15 (69%), and only one tumour (8%) had ODX-RS ≤ 25, and this is associated with substantial chemotherapy benefit. In the age group ≤ 50 years, 21 tumours were LVI +ve, and 18 tumours had ODX-RS ≤ 25 (86%), which is associated with no chemotherapy benefit; only 3 tumours (14%) had ODX-RS > 25, and this indicated substantial chemotherapy benefit. Conclusions: This study revealed that in the targeted patient population lympho-vascular invasion did not have a statistically significant impact on ODX-RS (p = 0.29).