Metastatic triple-negative breast cancer – current treatment strategies in the Nordics: a modified Delphi study

Background and purpose: This study aimed to assess current treatment strategies for metastatic triple-negative breast cancer (mTNBC) and the perceptions of clinical experts in Sweden, Denmark, Norway, Finland, and Iceland, comparing them to international guidelines to provide insights into how these therapies are implemented and adapted to national Nordic guidelines. Methods: A three-round modified Delphi method was followed with consensus defined as 70% agreement. A steering committee selected 20 experienced oncologists as panellists and developed the questionnaires. Questions included items related to treatment preferences in different treatment lines with different clinical scenarios in mTNBC patients. Results: In the first round, eight out of 33 questions on clinical treatment reached consensus with 14 out of 27 in the second round reaching consensus. In round three, eight out of eight questions reached consensus. The preferred treatment for mTNBC patients with PD-L1 positive was checkpoint inhibitors (CPI) in combination with chemotherapy. For patients with germline BRCA mutation and PD-L1 negative disease, PARP-inhibitors were preferred as 1L and sacituzumab govitecan (SG) in both 2L and later lines. Disagreement was observed for chemotherapy in later lines where evidence is sparse or lacking. Interpretation: The high level of consensus for new treatment strategies, such as CPI and PARP-inhibitors in 1L and SG in 2L or later lines, in comparison with the limited consensus for older treatments, such as chemotherapy, may reflect the growing academic evidence for different treatment strategies. Understanding the treatment patterns across different countries contributes to gaining consensus on the upcoming therapeutic advances.