A definition for aggressive disease in patients with HER-2 negative metastatic breast cancer: an expert consensus of the Spanish Society of Medical Oncology (SEOM).

PURPOSE: To converge on an expert opinion to define aggressive disease in patients with HER2-negative mBC using a modified Delphi methodology.

METHODS: A panel of 21 breast cancer experts from the Spanish Society of Medical Oncology agreed upon a survey which comprised 47 questions that were grouped into three sections: relevance for defining aggressive disease, aggressive disease criteria and therapeutic goals. Answers were rated using a 9-point Likert scale of relevance or agreement.

RESULTS: Among the 88 oncologists that were invited to participate, 81 answered the first round (92%), 70 answered the second round (80%), and 67 answered the third round (76%) of the survey. There was strong agreement regarding the fact that identifying patients with aggressive disease needs to be adequately addressed to help practitioners to decide the best treatment options for patients with HER2-negative mBC. The factors that were considered to be strongly relevant to classifying patients with aggressive HER2-negative mBC were a high tumor burden, a disease-free interval of less than 12-24 months after surgery, the presence of progressive disease during adjuvant or neoadjuvant chemotherapy and having a triple-negative phenotype. The main therapeutic goals were controlling symptoms, improving quality of life and increasing the time to progression and overall survival.

CONCLUSIONS: High tumor burden, time to recurrence after prior therapy and having a triple-negative phenotype were the prognostic factors for which the greatest consensus was found for identifying patients with aggressive HER2-negative mBC. Identifying patients with aggressive disease leads to different therapeutic approaches.