Highlights from

BCC 2019

St. Gallen International Breast Cancer Conference

Vienna 20-23 March 2019

St. Gallen Consensus - Neoadjuvant therapy and residual disease

Just as it was 2 years ago, almost all panellists (98.5%) endorsed neoadjuvant systemic treatment for patients with stage 2 or stage 3 triple-negative breast cancer, or with Her2-positive breast cancer. In addition, the panel this year voted about which type of neoadjuvant should be preferred in some specified subtypes of breast cancer. For example, in case of a postmenopausal patient with a luminal A subtype based on immunohistochemistry (or equivalent based on gene expression testing), 81% of the panellists preferred endocrine neoadjuvant therapy over neoadjuvant chemotherapy. This opinion means a clear shift in advantage of neoadjuvant endocrine therapy. Asked for their opinion on the appropriate duration of the endocrine neoadjuvant therapy in postmenopausal patients with a luminal A type tumour, 47% of the panellists preferred to continue endocrine neoadjuvant therapy until optimal reduction in tumour size is reached however long it takes, while 33% of the panellists preferred 6 month of endocrine neoadjuvant therapy.

There was no consensus at all on the issue of the use of a platinum-based regimen – in addition to an anthracycline/taxane based regimen – as neoadjuvant chemotherapy in patients with triple-negative breast cancer; 57% of the panellists voted against a platinum-based regimen, 35% agreed with a platinum-based regimen. On the other hand, platinum-based neoadjuvant chemotherapy was endorsed by 67% of the panellists for a patient with triple-negative breast cancer and a BRCA mutation. This prompted one of the panellists to say this is not in line with the scientific data showing that non-BRCA mutation carriers benefit most from platinum because BRCA mutation carriers are so chemosensitive that the addition of platinum on top of anthracycline/taxane does not add much extra benefit.

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