**2. Palliative care**

Although the history of PC services dates back many years, the first hospice in modern times was opened in the United Kingdom in 1967, and then it spread first to Western Europe and then to the rest of the world [8, 9]. The modern PC has emerged thanks to the groundbreaking work of Dame Cicely Saunders and the Hospice Movement that she started [10].

PC centers provide end-of-life services. This end of life is also referred to as terminal illness, with no common definition or clear time frame for when it occurs [11]. The National Cancer Institute defines the end of life as [12] "care given to people who are near the end of life and who no longer receive treatment to cure or control their disease."

56.8 million people worldwide need PC services, more than half of whom have priority [3]. Twenty-eight percent to 38% of these individuals are cancer patients [3, 13]. For terminally ill cancer patients who receive PC services, the last 6 months of their lives are particularly important, as their physical condition worsens and their symptoms get heavier, and during this time, their physicians tend to explain their prognosis [14–17].

The definition of PC is significant for presenting a framework for the service to be provided. This definition has evolved over time, taking its present form. Though defined by other authors before, the first definition was published by the WHO in 1990 [18], followed by a PC definition for children in 1998 [19]. By 2002, the definitions of PC for adults and children were revised [20] and in 2020, the current definition of PC has become as follows [3]:

*"Palliative care is an approach that improves the quality of life of patients (adults and children) and their families who are facing the problems associated with lifethreatening illness, through the prevention and relief of suffering by means of early identification and correct assessment and treatment of pain and other problems, whether physical, psychosocial or spiritual."*

It includes a comprehensive healthcare delivery system that involves preventive, curative, and rehabilitative health promotion services and PC services [5]. Hence, PC should be considered a healthcare need and a part of comprehensive healthcare services [21, 22]. Based on the definition, some characteristics of PC services include the following. Associated with life-threatening diseases, PC services pay more attention to the social aspect of patients compared to other healthcare services. Besides, the aim is to eliminate the patient's complaints and to increase their quality of life in their final days, rather than treatment. While doing this, PC considers the physical, psychosocial, and spiritual wishes of the patient. A higher quality of life for the

patient will increase the quality of life of their loved ones. For example, the patient and their loved ones will be able to go out and have a meal together or spend time in a park in nice weather. While other healthcare services center around the patient and their treatment, PC also considers the patient's close circle, their family, and the grieving process of the family.

Some other characteristics are not included in the definition of PC [3]: it considers death a normal process; it does not try to accelerate or delay death, rather it involves supporting the family in mourning after the patient's death.

Patients' relatives may have different expectations from PC. For example, some might expect PC services to prolong the patient's life rather than improve their quality of life. This does not fit the original philosophy of PC and causes numerous ethical problems, which will be mentioned further in this article.
