ASCO 2020: highlights in breast cancer

The 2020 Annual Meeting of the American Society of Clinical Oncology (ASCO) was held in a virtual format due to the ongoing SARS-CoV-2 pandemic. Despite these unique circumstances, results of several interesting studies in the field of breast cancer (BC) were reported. While overall survival data are still missing, KEYNOTE-355 suggests significant activity of pembrolizumab when added to first-line chemotherapy in metastatic triple-negative breast cancer. TBCRC 048 evaluated the role of olaparib in homologous recombination deficient tumours due to genomic alterations other than germline BRCA1/2 mutations; clinically relevant activity was reported in patients with germline PALB2 and somatic BRCA1/2 mutations. In HER2-positive early stage disease, different strategies of chemotherapy de-escalation are under investigation, but the optimal approach is still not well defined. Updated results from the HER2CLIMB trial show that the third-generation HER2 tyrosine-kinase inhibitor tucatinib in combination with trastuzumab and capecitabine is the new standard-of-care for pretreated patients with HER2-positive metastatic BC with active brain metastases. Results from BYLieve supports the notion that the combination of endocrine therapy with the PIK3Ca inhibitor alpelisib is a reasonable treatment approach in hormone-receptor positive/HER2-negative BC after prior CDK4/6-inhibitor therapy. Finally, the ECOG-ACRIN 2108 trial failed to show a benefit for early surgery of the primary tumour in patients with metastatic BC.