6. Patient currently receiving targeted therapy plus endocrine therapy (ET+TT) or endocrine therapy (ET) as per approved Health Canada indication or as per available expanded treatment protocol(s) or compassionate access program in either the 1st, 2nd or 3rd line advanced metastatic setting. Date of initiation of treatment should be a maximum of one month prior to the date of enrollment in this study. 1st, 2nd and 3rd line therapy in the advanced setting is defined as the first, second and third treatment respectively in the metastatic setting (which could include endocrine monotherapy, targeted therapy combination with endocrine therapy or chemotherapy).