The lack of standard definitions in the supportive and palliative oncology literature

Multiple organizations have raised concerns about the lack of standard definitions for terminology in the supportive and palliative oncology literature.

We aimed to determine 1) the frequency of 10 commonly used terms in the supportive and palliative oncology literature, 2) the proportion of articles that provided definitions for each term, and 3) how each term was defined.

We systematically searched MEDLINE, PubMed, PsycINFO, the Cochrane Library, Embase, ISI Web of Science, and Cumulative Index to Nursing and Allied Health Literature for original studies, review articles, and systematic reviews related to palliative care and cancer in the first six months of 2004 and 2009. We counted the number of occurrences for "palliative care," "supportive care," "best supportive care," "hospice care," "terminal care," "end-of-life," "terminally ill," "goals of care," "actively dying," and "transition of care" in each article, reviewed them for the presence of definitions, and documented the journal characteristics.

Among the 1213 articles found, 678 (56%) were from 2009. "Palliative care" and "end-of-life" were the most frequently used terms. "Palliative care," "end-of-life," and "terminally ill" appeared more frequently in palliative care journals, whereas "supportive care" and "best supportive care" were used more often in oncology journals (P<0.001). Among 35 of 601 (6%) articles with a definition for "palliative care," there were 16 different variations (21 of 35 articles used the World Health Organization definition). "Hospice care" had 13 definitions among 13 of 151 (9%) articles. "Supportive care" and other terms were rarely defined (less than 5% of articles that used the term).

Our findings highlight the lack of definitional clarity for many important terms in the supportive and palliative oncology literature. Standard definitions are needed to improve administrative, clinical, and research operations.