Highlights from

BCC 2019

St. Gallen International Breast Cancer Conference

Vienna 20-23 March 2019

St. Gallen Consensus - Gene expression signatures

The use of gene expression signatures is becoming increasingly important in risk stratification and treatment decision-making for patients with early breast cancer. At the St. Gallen Conference 2017 a majority of the panellists took the view that results of gene expression signature tests like Oncotype DX and MammaPrint are prognostic for recurrence of disease within 5 years after surgery. In recent years, the results of MINDACT [1], TAILOR-X [2] and the PLAN-B trial [3] have been published. Based on the results of these trials, almost all panellists (94%) were in favour now of using these gene expression signatures as a decision aid for adjuvant systemic therapy in patients with ER+/Her2-, T1/T2, N0 breast cancer. In case of ER+/Her2-, T3, N0 breast cancer, 75% of the panellists found gene expression signatures to be valuable for determining whether to recommend adjuvant systemic chemotherapy. Also in case of patients with ER+/Her2- (any T) and 1 to 3 positive lymph nodes, a majority (80%) of the panellists was in favour of using a gene expression signature. In case of a low risk MammaPrint in patients with 1 or 2 positive lymph nodes, 80% of the panellists voted against an indication for adjuvant chemotherapy, irrespective of age. In line with this, 80% of the panellists voted against an indication for adjuvant chemotherapy in patients (older than 50 years) with 1 or 2 positive nodes and an Oncotype DX Recurrence Score <11. Remarkably, 51% of the panellists took the view that patients younger than 50 years, with node-negative disease and an Oncotype DX Recurrence Score of 21 to 25 should be advised adjuvant chemotherapy. This is in contrast with the results of TAILOR-X, which showed little benefit of adjuvant chemotherapy for patients younger than 50 years, node-negative disease and an Oncotype DX Recurrence Score <25. With regard to postmenopausal, node-negative patients having an Oncotype DX Recurrence Score >26, 57% of the panellists agreed that these patients should be offered adjuvant chemotherapy depending on (unfavourable) histopathological parameters and patients preferences, while 39% of the panellists voted that these patients should be offered adjuvant chemotherapy routinely.

  1. Cardoso F, et al. N Engl J Med 2016; 375:717-729.
  2. Sparano JA, et al. N Engl J Med 2018; 379:111-121.
  3. Nitz U, et al. J Clin Oncol. 2019; 37: 799-808.

The content and interpretation of these conference highlights are the views and comments of the speakers/authors.