Palliative care is an interdisciplinary medical caregiving approach aimed at optimizing quality of life and mitigating suffering among people with serious, complex, and often terminal illnesses. Within the published literature, many definitions of palliative care exist. The World Health Organization (WHO) describes palliative care as "an approach that improves the quality of life of patients and their families facing the problems associated with life-threatening illness, through the prevention and relief of suffering by means of early identification and impeccable assessment and treatment of pain, illnesses including other problems whether physical, psychosocial, and spiritual". In the past, palliative care was a disease specific approach, but today the WHO takes a broader patient-centered approach that suggests that the principles of palliative care should be applied as early as possible to any chronic and ultimately fatal illness. This shift was important because if a disease-oriented approach is followed, the needs and preferences of the patient are not fully met and aspects of care, such as pain, quality of life, and social support, as well as spiritual and emotional needs, fail to be addressed. Rather, a patient-centered model prioritizes relief of suffering and tailors care to increase the quality of life for terminally ill patients.