Looking Back From Death: The Value of Retrospective Studies of End-of-Life Care
Authors: Craig C. Earle, John Z. Ayanian
Journal: Journal of Clinical Oncology (2006)

Cancer is projected to cause more than 570,000 deaths in the United States in 2005. As patients with cancer approach death, the issues they face are often similar regardless of the original site of disease. Important practice variation has been documented near the end of life, with inadequate treatment of pain and other symptoms, increasing use of overly aggressive anticancer treatments, and disparities in access to hospice services. As a result, the quality of end-of-life care delivered to patients who die as a result of cancer is a major public health concern. Two approaches have commonly been used to study the quality of end-of-life care. Many studies have retrospectively assessed the care received by patients in the time frame leading up to death, whereas others have identified patients entering the terminal phase of disease and prospectively observed their care forward in time. Each of these approaches has its theoretical and practical advantages and disadvantages, yet it has been suggested recently that retrospective designs are particularly biased and thus should be “laid to rest.” This sweeping recommendation, however, risks the loss of important opportunities to understand and improve end-of-life care in large representative cohorts of patients with cancer. In a perfect world, the optimal way to study end-of-life care, assuming unlimited resources, cooperation, and time, would be to assemble a cohort of all patients with incident disease, regardless of initial stage or severity, and collect data on their care until all of them have died. This study design provides an unbiased look at care before death among those who died, and also allows study cohorts to be defined by sentinel events among those who went on to die as a result of their disease and those who did not. However, obtaining information from a representative sample is particularly challenging. If one is able to identify patients who are entering the terminal phase and approach them quickly enough, they are often by definition very ill and unable to provide information. Although such studies have been conducted successfully, they are expensive and laborious, making alternative study designs attractive. There are two alternatives: less-than-optimal prospective approaches to define study cohorts and retrospective approaches to this task. In retrospective studies of end-of-life care, the cohort consists of decedents. These participants can be either patients who died as a result of a particular disease (as determined by death certificate, for example) or patients with a particular disease who died as a result of any cause. Investigators then look back over the time leading up to death to observe preterminal care. Retrospective designs have several advantages over prospective designs. First, they allow for easy identification of cohorts of relevant patients. In contrast, prospectively identifying patients who are approaching the end of life is often not feasible— especially from administrative data sources. Second, a retrospective approach allows all patients who come to the end of life to be studied, not just a nonrandom subset defined by a disease characteristic or event that identifies them as dying. For example, assembling a prospective cohort based on hospice enrollment will only capture those patients whose physicians recognized that they were approaching the end of life, whose physicians were able to raise this difficult issue with them, and who themselves philosophically accepted hospice care. In another example, it has been suggested that analysis of end-of-life care be restricted to patients presenting with metastatic breast cancer, rather than looking at all patients who die of breast cancer. Less than 20% of the patients who die as a result of breast cancer initially present with clearly terminal disease, however, and these patients have been shown to have different characteristics from those who initially present with earlier stage cancer and then later relapse. Unfortunately, relapse of cancer is not accurately or completely captured by most tumor registries. A prospective cohort study of patients with metastatic breast cancer at diagnosis would yield no information about the majority of patients who die as a result of breast cancer. In addition, there is great variability in the natural history and effectiveness of therapies among patients with metastatic cancer, such that some patients with incurable metastatic breast cancer may be “terminally ill” for several years. In those situations, their initial care will not be focused on end-of-life issues. Without research using retrospective designs, the end-of-life experiences of patients not easily defined as dying will often be overlooked. Lastly, by only assessing the end-of-life care of patients who actually die, efficient retrospective designs facilitate the development of performance measures that can be used with readily available data to monitor end-of-life care across providers, geographic areas, demographic groups, and time periods. Such performance measures may become key elements of new national systems to monitor and improve the quality of cancer care. JOURNAL OF CLINICAL ONCOLOGY E D I T O R I A L VOLUME 24 NUMBER 6 FEBRUARY 2