To Örebro University

Background: The aim of this Delphi study was to assess current perspectives on HR+/HER2- advanced breast cancer (aBC) treatment strategies among Nordic BC oncologists, and to gain broader understanding of the uptake and implementation of novel treatments.

Methods: A modified, three round Delphi method was followed. A steering committee was appointed for study coordination, panellist selection and questionnaires development. The questionnaires covered clinically relevant topics related to HR+/HER2- aBC treatment: treatment patterns in different lines of therapy (first- (1L), second- (2L) and third-line (3L)), oligometastatic disease, de novo aBC, brain metastases, age as influential factor, visceral crisis, radiotherapy, diagnostics and clinical guidelines. Both open and closed-ended questions were included. Consensus was defined as at least 70% agreement.

Results: In total 28 panelists participated in the study. In rounds one and two, 14 and 21 questions reached consensuses, respectively. Thirteen non-consensus reaching questions were reposted in round three, where 10 reached consensus. Overall, topics that reached a high consensus level included: treatment approaches in 1L and 2L treatment setting for HR+/HER2- aBC, treatment of oligometastatic disease, visceral crisis and brain metastases, and age-related treatment considerations. No consensus was reached for aspects regarding 3L therapy and de novo aBC. Endocrine therapy (ET) combined with CDK4/6i was the treatment of choice for both 1L and 2L therapy. Regarding implementation of clinical guidelines, a discrepancy was observed between treatments recommended in guidelines and those used in clinical practice, especially in cases where novel treatments were proposed.

Conclusions: Endocrine therapy combined with a CDK4/6i is the frontline treatment choice for HR+/HER2- aBC in the Nordics. Observed discrepancies between international clinical guidelines and practice are partly due to difference in the availability of novel treatment strategies that might lead to differences in clinical experience in the Nordics. The lack of consensus might reflect limited evidence on these topics and the need for collaborative research efforts. Written on behalf of Nordic Delphi Panellist group.