Medical treatment decision-making capacity and neuropsychological functioning in terminally ill cancer patients

Patients with advanced cancer must make many important treatment decisions, including whether to consent to DNR orders, the introduction of palliative care services, and decisions about the continuation or discontinuation of life-prolonging or sustaining treatment. As their disease progresses, many cancer patients experience impaired decision making capacity that may be the result of age, hospitalization, cancer treatment side effects or the cancer itself. This study is the first to examine decision-making capacity and its assessment in terminally ill cancer patients relative to the four most commonly used legal standards of competency: ability to express a choice, understanding, appreciation, and reasoning. The nature of decisional impairment in a sample of terminally ill cancer patients was assessed using a comprehensive measure of decision-making capacity, the MacCAT-T. Additionally, measures of neuropsychological functioning were administered to identify the cognitive underpinnings of decision-making capacity. Finally, the study examined concordance between physician-rated determinations of capacity and performance on the MacCAT-T. The performance of terminally ill cancer patients was compared to a community sample of demographically similar participants who were not severely ill. The results of the MacCAT-T and measures of neuropsychological functioning revealed strikingly high rates of decisional and cognitive impairment. Most participants in the terminally ill sample were at least somewhat impaired in their ability to make medical decisions. In addition, there were high rates of cognitive impairment across neuropsychological domains in the terminally ill sample. Decisional capacity was related to general cognitive functioning which suggests that at the end of life, decision-making capacity may be a more broad, rather than domain-specific ability. Physicians\u27 ratings of capacity status were often incongruent with their patients\u27 performance on the MacCAT-T, as they both over-and under-estimated decisional impairment. These results underscore the necessity for conducting research to inform best practices in end-of-life care. Future studies should focus on the longitudinal course of cognitive impairment in cancer and the development of a systematic method for capacity assessment that will allow clinicians to better preserve the autonomy of their patients and protect them from harm