De-escalating systemic therapy in triple negative breast cancer: The example of secretory carcinoma.

Triple negative breast cancers have the highest relapse risk and the least favourable prognosis of all breast cancer subtypes, leading to an escalation of chemotherapy, substantially during recent years. Secretory carcinoma of the breast is a rare triple negative neoplasm, first described in children but more often presenting in adults. We report a case of a 70-years-old woman, initially diagnosed on the biopsy with a triple negative infiltrating Not Otherwise Specified (NOS) carcinoma of the breast, before it was later correctly identified as a secretory carcinoma, notably because of an abundant intra and extracellular secretory material. This new diagnosis, confirmed by fluorescence in-situ hybridization analysis showing ETS variant 6 (ETV6) gene rearrangement, allowed the de-escalation of chemotherapy therapy. Four years later, the patient is free of recurrences.