Therapeutic modalities for metastatic breast cancer have not stopped progressing in recent years, in particular hormonotherapy targeting hormonal receptors (HR), and targeted therapies targeting Human Epidermal Growth Factor Receptor-2 (HER2), which allowed to improve the overall survival of patients over expressing these receptors, however, the high risk of metastatic relapse makes the prognosis remain impaired. Among the causes of these relapses, the phenotypic instability, which would be at the origin of expression change of the HR and HER 2 on the surface of tumor cells.This discordance of phenotypic expression between the primary tumor and the metastatic relapse leads to an assessment of therapeutic modalities initially undertaken? Through this work, we will compare our study about 17 female flight crew with metastatic breast cancer, conducted at the aerospace medical center of the military hospital Mohamed 5 of Rabat, with literature data