QOL and Outcomes Research in Prostate Cancer Patients With Low Socioeconomic Status
QOL and Outcomes Research in Prostate Cancer Patients With Low Socioeconomic Status
Adenocarcinoma of the prostate the most common solid tumor in American men, is responsible for tremendous morbidity and mortality in this country, and yet controversy governs most discussions of screening, diagnosis, and treatment. Central to any study of outcomes in prostate cancer must be an examination of health-related quality of life. Toward this end, quality of life research in this area of urologic oncology has rapidly expanded over the last several years. Indeed, when differences in survival cannot be demonstrated among treatments, quality of life may be the deciding factor in difficult choices faced by men with early- or late-stage disease.
Prostate cancer exacts a greater human toll in disadvantaged populations, such as poor, underserved, and African-American men. Nevertheless, quality-of-life research focused on this demographic segment of society has been lacking. Although most studies do include some minority patients, they typically make up a small fraction of any study sample. Hence, most of the quality-of-life literature in prostate cancer is drawn from highly educated, affluent population samples obtained from a variety of tertiary academic hospitals in the United States. Although data from these centers have provided an important foundation for a relatively young field, they have largely ignored the patients who often suffer most from the effects of prostate cancer.
The VA CaPOS Database
The article by Kim and colleagues, written under the direction of Dr. Charles Bennett, a well-known prostate cancer outcomes researcher, describes an important initiative aimed at remedying this deficit in the literature. In fact, lessons already learned from the VA Cancer of the Prostate Outcomes Study (VA CaPOS) have made a valuable contribution to the state of knowledge in this discipline, and they promise to unlock many more secrets from an understudied population unduly burdened by prostate cancer.
Thus far, several interesting revelations have come to light from research in this special population. First, quality of life and other patient-centered outcomes can be reliably measured in patients of low literacy and socioeconomic status. This confirms that although the methodology must be altered into a more contextually appropriate format, quality-of-life assessments can, in fact, be made in this patient population.
Second, participation and response rates are high. This indicates that men of low socioeconomic status have both the interest and the willingness to talk about their physical, emotional, and social responses to illness.
Third, as prostate cancer advances, quality-of-life domains are highly responsive to change. As in the majority population, this finding supports the use of quality-of-life measurements as important outcome variables in both clinical and research studies of minority populations.
Fourth, utilities for impaired health states, although often difficult to measure in even the most educated subjects, can be assessed and used to provide meaningful insights into medical decision-making among underprivileged individuals.
Finally, Kim and colleagues results suggest that, contrary to conventional wisdom, African-American ethnicity may not be as strong a predictor of late presentation in prostate cancer as is commonly believed. In multivariate analyses that control for both race and literacy, neither variable appears to have a significant impact on who is diagnosed with advanced-stage tumors. Clearly, further work needs to be done in this area to explore interactions between these and other variables.
The CaPSURE Database
As noted by the authors, chronic disease databases have proven to be extraordinarily useful for several other conditions.[1,2] Another example of a large, observational database is the Cancer of the Prostate Strategic Urologic Research Endeavor (CaPSURE), a national, multisite cohort initiated in 1995 as a longitudinal, observational database of patients with biopsy-proven prostate cancer. It includes all stages of disease and a wide range of treatments.
Patients in a variety of academic and community-based settings are invited by their urologists to join the study. Extensive clinical data are submitted by the urologist at baseline and after every follow-up visit. Every 3 to 6 months, patients complete surveys that include health-related quality of life, economic impact, satisfaction with care, and many other patient-centered outcomes related to prostate cancer and its treatments. Data quality are strictly managed with well-established protocols by a research team at the University of California, San Francisco. Presently, CaPSURE has accrued over 4,000 patients from 29 sites across the United States.
Quality-of-life data are collected with established, validated instruments that include the RAND 36-Item Health Survey (SF-36)[4,5] as a measure of general health-related quality of life and the UCLA Prostate Cancer Index[6,7] as a disease-specific measure, as well as a case-mix adjustor and a series of sociodemographic items. The psychometric properties of the instruments in this population include high levels of reliability and validity.[8,9]
Findings From CaPSURE
During a longitudinal CaPSURE study that examined the effect of sociodemographic factors on quality of life, married patients enjoyed better emotional well-being and family functioning at baseline (P < .02). However their family functioning declined over the first 9 months after diagnosis and treatment (P = .0006).
Older patients had slightly better baseline performance in several quality-of-life domains but experienced greater decrements over time than did younger patients. Baseline quality of life was worse with increasing comorbidity and better with earlier tumor stage at diagnosis. Initial decreases in quality of life were followed by improvement in both general and diseasespecific quality of life over the next 9 months.
Another CaPSURE study examined whether urologists caring for men with prostate cancer could accurately capture the nuances of quality of life as disclosed by patients. Significant differences (P £ .002) were seen between physician and patient assessments of clinical domains, such as physical function, fatigue, bone pain, sexual function, urinary function, and bowel function. In all domains, urologists underestimated the presence of patient symptoms causing impairment in health-related quality of life. This underscored the axiom that quality-of-life data are best reported not by doctors, but rather, by patients themselves.
Observational databases, such as VA CaPOS and CaPSURE, are rich sources of important information for patients making decisions about therapy for early- or advanced-stage prostate cancer. Traditionally, the primary end points in most treatment evaluations have been cure and survival, but the world spotlight is now focusing increased attention on patient-centered outcomes, such as quality of life in prostate cancer. This outcome can even be a robust predictor of mortality.
With quality of life assuming an ever-increasing role as a primary end point in prostate cancer studies, it is in-cumbent on researchers to aggressively include the many different segments of the patient population in those studies.
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