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The quality of life is determined by its activities.
We can agree that Aristotle had it largely right. But Aristotle’s concept focuses solely on a person’s ability to engage in activities. Thoughtful and explicit evaluation of the many facets of quality of life (QOL) is highly relevant to patients with brain tumors. Accordingly, health-related QOL is a frequent secondary endpoint in clinical papers in this area.
You have seen us address the topic in at least three articles already published this year. In the February 2009 issue, we carried a special focus section containing three articles on QOL in glioma patients. We take up the topic again in the current issue, which carries a clinical investigation from University of California, San Francisco, researcher Susan M. Chang and several of her associates (“Quality of life in adults with brain tumors: Current knowledge and future directions,” page 330). This paper looks at the evidence from studies of adults with high- and low-grade brain tumors of many histologic types and dissects the current state of knowledge; its aim is to identify the areas of greatest need and greatest promise.
Because QOL is itself a multifaceted concept, it will not surprise you that the challenges of its assessment are diverse and difficult.
For instance, it is hard to determine the QOL of long-term survivors of brain tumors. As survival times continue to lengthen because of therapeutic improvements, determining QOL for long-term survivors will become increasingly important. It may be particularly important to tease out what factors are most relevant to QOL and how the effects on overall QOL change over time, as noted by Cheng et al. in February (“Health-related quality of life in patients with high-grade glioma,” page 41). This month, Chang et al. point out that the current literature on survivorship suggests that long-term QOL may be acceptable, even if mood and cognition are negatively impacted. However, the authors note, most of this evidence comes from “small, mostly retrospective, noncontrolled studies,” with patient populations and follow-up times varying widely. Prospective analyses, particularly with QOL as a primary endpoint, are sorely needed.
A lack of validated, comprehensive measurement instruments has also impeded progress in QOL assessment for brain-tumor patients. In particular, longitudinal analyses of these patients are prone to incomplete data and loss of follow-up. Documenting the reasons for such losses is important, say Chang et al.: “One of the dangers of not adequately considering missing data is that the sickest patients with the highest symptom burden do not fill out questionnaires and are underrepresented in studies.” Among the proposed solutions is redesigning test instruments to be not only multifactorial (as is the current trend) but also simple for patients to use. Cheng et al. observe that “proxy-reported [health-related] QOL questionnaires need to be developed for those patients who cannot self-report,” and these instruments, as much as possible, must yield conclusions as the most effective self-reports do.
QOL research in brain-tumor patients must be especially sensitive to the interplay of patient-specific effects of the disease (the tumor’s precise location and its indolence or aggressiveness; patient age; baseline health status; social and financial support; and comorbidities) and treatment effects of radiation, chemotherapeutic agents, and medications for comorbid conditions. Determining what factors contribute to QOL and in what strength and direction with a single, easy-to-answer questionnaire may be an impossibility.
The questions of what QOL is, what affects it, how best to measure it, and how to support it for each patient will continue to be important to the practice of neuro-oncology and to this journal.