58 Introduction As patients live longer with MBC, quality of life becomes an increasingly important focus. Targeted treatment options and advances in supportive care are transforming MBC from a terminal illness associated with short survival into a disease many patients are living with over longer periods of time. Although median survival is still widely cited in the range of 2 to 4 years, many patients with ER+ and HER2+ MBC are living much longer. The most recent published data from SEER registries report 5-year survival of newly diagnosed de novo MBC (breast cancer that is already metastatic at the time of first diagnosis) to be 24.3% (ranging from 13.7% for black women over 50 years of age to 32.9% for white women under 50 years of age)[30] . Because of trends toward longer survival, some have used the word “chronic” to apply to MBC, but many patients and advocates take exception to this overly-optimistic term, believing that it trivializes the nature of what remains a deadly disease. The lengthened survival of MBC patients has had an impact on quality of life research. Psychosocial researchers are now concerned with more than just end-of-life issues, and “palliative care” has been repurposed earlier in the course of disease, to be initiated with metastatic diagnosis[31] . Background on Quality of Life Research Quality of life is a multidimensional concept, consisting of physical, emotional, social, and cognitive functioning, including the impact of disease symptoms and treatment side effects [32] . Over the past decade, MBC patients’ voices are being heard more frequently through support and advocacy organizations, through surveys, and in quality of life research that increasingly incorporates patient-reported outcomes. Historically, the field of psycho-oncology, which addresses the mental, social, and emotional burden of cancer, has been hindered by long-standing societal attitudes relating to not only fear of cancer, especially metastatic disease, but also the stigma associated with mental illness[33] . Beginning in the 1970s, behavioral medicine began to develop models of how patients cope with and adapt to living with serious physical illness and disability and to quantify psychosocial issues so that they could be reliably measured. This paved the way to broader use of symptom assessment, studies of unmet patient needs, and screening for psychosocial distress—not only in research but also in standards of care for patients. For example, National Comprehensive Cancer Network guidelines now recommend the incorporation into standard care of an instrument that measures “distress,” a term chosen because it is believed to be less stigmatizing than terms like “depression” and “anxiety” associated with mental illness[34] . In 2007, an Institute of Medicine (IOM) panel examined psychosocial issues for cancer patients and issued recommendations[35] , noting the presence of anxiety and depression, the lack of information available to patients to help them manage their illness, and an absence of resources to address these issues. Better communication between patients and providers, routine assessment of needs, patient engagement, and development of care plans were among the IOM recommendations. Oncology researchers and key opinion leaders have issued a strong call for treating the patient as a whole person, rather than merely as a disease or a cluster of symptoms.