Highlights from

BCC 2019

St. Gallen International Breast Cancer Conference

Vienna 20-23 March 2019

Selection of patients for neoadjuvant chemotherapy treatment based on oncotype recurrence score in luminal breast cancer

Multigene signatures, e.g. the Oncotype DX Breast Recurrence Score, are increasingly used to guide adjuvant treatment decisions in patients with early breast cancer. Dr Ariadna Gasol Cudos (Hospital Universitari Arnau de Vilanova de Lleida, Spain) explored the possible use of the Oncotype DX Breast Recurrence Score to select patients with luminal breast cancer to receive neoadjuvant chemotherapy [1].

Neoadjuvant chemotherapy is considered an optimal option in early breast cancer specially in Her2-positive and triple-negative phenotypes, but in luminal ones remains controversial, so a more accurate selection is necessary. Oncotype Recurrence Score (RS) is a validated test to select luminal patients to receive adjuvant chemotherapy.

In 77 consecutive with breast cancer considered candidates to receive chemotherapy (based on clinical variables such as initial tumour size or lymph node involvement), Gasol Cudos et al. performed an Oncotype DX test and analysed the score results and its correlation with response. Median age of the patients was 55 (range 32–84), median tumour size was 36.78 mm (20–100), and 44 tumours (55.7%) had initial node involvement. Median oestrogen expression was 259 histoscore, progesterone 111, and median Ki67 was 32%. Obtained median Oncotype RS was 23 (6–76); 6 (7.8%) of low risk (RS <11), 52 (67.5%) of intermediate risk (RS 11–30), and 19 (24.7%) of high risk (RS >31).

Using a threshold of 25; 48 (62%) patients were of low risk and 29 (38%) patients were of high risk. Final neoadjuvant chemotherapy was administered in 50 patients (63%); the 27 other patients underwent surgery. However, 5 patients received adjuvant chemotherapy due to major node involvement. Pathologic response after neoadjuvant chemotherapy in 46 patients was: 5 with RCB-0 (9.8%); 8 RCB-I (15.7%); 13 RCB-II (25.5%), and 20 RCB-III (39.25). Highest histological response (RCB-0 + RCB-I) was observed in 10/26 (38.5%) patients of RS >25 and 15% (3/20) patients of RS <25.

Based on these results, Gasol Cudos et al. concluded that the Oncotype DX RS could be a useful tool to select neoadjuvant chemotherapy in luminal breast cancer. Neoadjuvant chemotherapy could be avoided in 37% of patients, but few patients will still need adjuvant chemotherapy because of nodal involvement despite of low risk RS. Major responses are observed in patients with RS >25.

  1. Gasol Cudos A, et al. The Breast 2019; 44 (suppl 1): abstract P166.

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