The Oncotype DX assay uses expression of 21 genes to predict the risk of distant disease recurrence in patients with oestrogen receptor positive Her2 negative breast cancer. It has been demonstrated that increased intra-tumoural inflammation is associated with higher Oncotype score. An inflammatory milieu within the breast is associated with more aggressive histological cancer subtypes, and also with obesity, which is recognised as a risk factor for breast cancer. The association between obesity and breast cancer is higher in post-menopausal than pre-menopausal women. Therefore this study aimed to investigate whether there is a correlation between Oncotype score, menopausal status and obesity.
All patients with Oncotype assays performed between 2008 and 2016 in several centres in Ireland were identified. Data was retrospectively collected on weight, body mass index (BMI), menopausal status and Oncotype scores, including oestrogen (ER) and progesterone (PR) scores. Statistical analysis assessed correlation between Oncotype scores and these factors.
Analysis was performed on 269 patients from a single centre with early stage breast cancer. Median age was 53.4 years and the majority of patients (58%) were post-menopausal at diagnosis. Patients who had a BMI less than 25 (normal weight) had significantly lower Oncotype score than those with BMI greater than 25 (overweight/obese) (p
Oncotype score is higher in overweight patients with early stage node-negative breast cancer. This difference appears to be independent of ER and PR scores and correlates with menopausal status. This retrospective study is the first to suggest that the body mass index and menopausal status of patients with early stage breast cancer may influence the Oncotype DX recurrence score and analysis of a further cohort of patients is ongoing.
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All authors have declared no conflicts of interest.