Low oncotype recurrence score (RS) and poor clinical outcomes: An irish multicentre experience.

e11586 Background: Oncotype RS is used to assess recurrence risk and predict chemotherapy benefit for hormone positive, node negative, early stage breast cancer. There is a predicted recurrence rate of 6.8% at 10 years with an RS of less than 18, considered low, with the use of hormonal treatment alone. We sought to identify patients with a low RS who subsequently relapsed and to identify any clinicopathologic factors that might allow for futher optimisation of risk stratification. Methods: Using prospectively maintained institutional databases in seven tertiary level Irish cancer centres we identified all patients in these centres with node negative hormone positive breast cancers suitable for chemotherapy, referred for Oncotype Dx testing. We retrospectively examined baseline clinical characteristics, mode of detection of breast cancer and histopathological features of the surgical resection specimens. RS were identified and Recurrence Score-Pathological Criteria (RSPC) was also calculated for each pati...