Development and validation of the expanded prostate cancer index composite (EPIC) for comprehensive assessment of health-related quality of life in men with prostate cancer

Abstract

Objectives. Health-related quality of life (HRQOL) is an increasingly important endpoint in prostate cancer care. However, pivotal issues that are not fully assessed in existing HRQOL instruments include irritative urinary symptoms, hormonal symptoms, and multi-item scores quantifying bother between urinary, sexual, bowel, and hormonal domains. We sought to develop a novel instrument to facilitate more comprehensive assessment of prostate cancer-related HRQOL. Methods. Instrument development was based on advice from an expert panel and prostate cancer patients, which led to expanding the 20-item University of California-Los Angeles Prostate Cancer Index (UCLA-PCI) to the 50-item Expanded Prostate Index Composite (EPIC). Summary and subscale scores were derived by content and factor analyses. Reliability and validity were assessed by test-retest correlation, Cronbach's alpha coefficient, interscale correlation, and EPIC correlation with other validated instruments. Results. Test-retest reliability and internal consistency were high for EPIC urinary, bowel, sexual, and hormonal domain summary scores (each r Ն0.80 and Cronbach's alpha Ն0.82) and for most domain-specific subscales. Correlations between function and bother subscales within domains were high (r Ͼ0.60). Correlations between different primary domains were consistently lower, indicating that these domains assess distinct HRQOL components. EPIC domains had weak to modest correlations with the Medical Outcomes Study 12-item Short-Form Health Survey (SF-12), indicating rationale for their concurrent use. Moderate agreement was observed between EPIC domains relevant to the Functional Assessment of Cancer Therapy Prostate module (FACT-P) and the American Urological Association Symptom Index (AUA-SI), providing criterion validity without excessive overlap. Conclusions. EPIC is a robust prostate cancer HRQOL instrument that complements prior instruments by measuring a broad spectrum of urinary, bowel, sexual, and hormonal symptoms, thereby providing a unique tool for comprehensive assessment of HRQOL issues important in contemporary prostate cancer management. A s prostate cancer is increasingly diagnosed at early stages with favorable survival outcomes, the basis on which patients select primary therapy has shifted toward consideration of health-related quality of life (HRQOL). 1,2 However, no HRQOL instrument has previously been developed and validated in a setting concurrently representing each of the three most common current interventions Supported by National Institutes of Health grants 5P30CA46598 and 1P50CA69568 (National Cancer Institute Prostate Cancer Specialized Projects of Oncology Research Excellence [SPORE]), American Cancer Society Clinical Career Development Award 96-77 (M.G.S.), Robert Wood Johnson Scholars Program (J.T.W.), and American Foundation for Urological Diseases Fellowship Award (J.T.W.). From the Veterans Affairs Center for Practice Management and Outcomes Research; Ann Arbor Veterans Affairs Medical

The association of treatment‐related symptoms with quality‐of‐life outcomes for localized prostate carcinoma patients

“…However, because better health-related quality of life was observed for both cases and controls in our study compared with the earlier findings of Litwin and colleagues, it is unlikely that advances in prostate carcinoma treatment alone account for all of the difference. More extensive measures of urinary, bowel, and sexual functioning, such as those recently developed by Wei and colleagues 37 also may provide further insight regarding the specific quality-of-life impact of various symptoms associated with localized prostate carcinoma.…”

Long-term Health-related Quality of Life After Primary Treatment for Localized Prostate Cancer: Results from the CaPSURE Registry

“…However, both studies measured urinary function using the UCLA PCI, which focuses primarily on urinary incontinence rather than irritating or obstructive symptoms, and, therefore, reflects the impact of surgery on urinary function to a greater extent than that of radiation or local tumor progression. Studies using other measures, such as the Expanded Prostate Cancer Index Composite (EPIC) [16], have reported consistently that surgery resulted in more incontinence but less irritating and obstructive symptoms [2,5]. As of 2012, CaPSURE has switched to using EPIC to provide a more comprehensive assessment of urinary HRQOL.…”

Use of quality indicators to evaluate the care of patients with localized prostate carcinoma

“…During the intercurrent period, our interest in measuring outcomes led to the development of novel, validated instruments for this purpose (EPIC). 15 Accordingly, compliance with documentation of posttreatment function increased from 0% to 46% between 1995 and 2000 (P Ͻ 0.0001). Now, health-related quality-of-life data are obtained routinely for all patients treated at our institution to further enhance our understanding of functional outcomes after surgery.…”

“…The validated instrument currently in use at the University of Michigan for patient assessment of urinary, sexual, and bowel function after primary therapy is the Expanded Prostate Cancer Index Composite (EPIC). 15 EPIC results are maintained routinely in our prostate cancer data base. Therefore, measurement of compliance with candidate indicators P6, O21, and O22 was feasible by querying the prostate cancer data base (Table 1).…”