[Clinical management of a patient with non-triple-negative breast cancer who converts to a triple-negative subtype at recurrence.]

The management of patients with advanced breast cancer is becoming increasingly complex compared to the past, mainly due to numerous therapeutic innovations introduced in the current therapeutic scenario. At the time of metastatic disease diagnosis, as indicated by the guidelines, it is important to perform a biopsy of the metastatic sites to optimize choices and expand therapeutic options. Approximately 25-45% of patients who experience a recurrence of the primary tumor lose hormone receptor expression: in this context, solid data comes from a subanalysis of the randomized clinical trial ASCENT, in which the benefit of a treatment with antibody-drug conjugate sacituzumab govitecan is also confirmed in case of non-triple negative breast cancer at diagnosis that subsequently convert to a triple negative subtype. The case reported below is representative of this clinical situation.