The development of HRQOL instruments requires a balance between clinical usefulness and comprehensiveness. Lengthy HRQOL questionnaires can often be shortened, eliminating redundant items, while minimizing sacrificed validity, as has been achieved during the development and validation of the AUA-SI 5
and other tools 3,4
. The 8-item AUA-SI was developed from an initial 16 questions, which were reduced to one bother item and 7 function items. Of the function questions, 6 (emptying, frequency, intermittency, urgency, weak stream and nocturia) were retained for their high correlation with the bother item while the hesitancy item was kept for content.
The UCLA-PCI was selected as the foundation for the EPIC because, at the time of EPIC development, the UCLA-PCI had already been broadly used, had robust construct validity and was the first instrument to have been validated for measurement of patient-reported outcomes in early stage prostate cancer. The initial 50-item version of the EPIC instrument retained 17 of the original UCLA-PCI questions; retained and refined the assessment of urinary incontinence, bowel/rectal, and sexual domains that comprised the range of HRQOL queried by UCLA-PCI; and expanded the scope of HRQOL assessment to include urinary irritative/obstructive and vitality/hormonal domains not covered in the UCLA-PCI. The brief format of EPIC-26 retains these 5 domains and 12 of the original UCLA-PCI questions, achieving the goal of being both clinically useful and retaining the comprehensiveness of the original EPIC.
EPIC-26 has been used in a multi-center, prospective study of change in prostate cancer HRQOL after primary treatment for early stage prostate cancer in 1201 men 9
. Findings from this study, which are relevant to general use of the EPIC-26, include observed pre-treatment EPIC HRQOL scores that can be considered as reflecting norms among men with early stage prostate cancer who have not yet undergone treatment. The mean pre-treatment scores were 93.5 for urinary incontinence, 87.8 for urinary irritation/obstruction, 95.9 for bowel/rectal, 70.7 for sexual and 92.1 for the vitality/hormonal HRQOL domain scores.
Several other instruments have been developed for measuring prostate cancer-specific HRQOL outcomes. The 29-item instrument developed by Clark and Talcott 10
was validated in patients treated with prostatectomy or external-beam radiation, spanning urinary incontinence and irritation/obstruction, bowel and sexual domains, but did not include questions in the vitality/hormonal domain. The instrument used by Madalinska et al. 2
consists of the UCLA-PCI urinary and bowel domains and a sexual function module previously developed in patients with erectile dysfunction 11
, as the UCLA-PCI sexual domain was deemed insufficiently detailed. It does not include a vitality/hormonal or urinary irritation/obstruction domain. The tool published by Giesler et al. 12
consists of urinary, sexual, bowel and cancer worry domains. While it includes a unique anxiety domain, the 52-item tool is lengthy and does not distinguish between urinary incontinence and irritative/obstructive symptoms. The 12-item FACT - Prostate module 13
was developed in patients with more advance prostate cancer than the setting queried by EPIC and does not distinguish between urinary, bowel, sexual and vitality/hormonal domains, providing a single summary score instead of individual domain scores. The 17-item Prostate Cancer Outcomes Study 14
used 5 of the original UCLA-PCI urinary incontinence and bowel questions along with a new sexual function domain, but it did not include urinary irritation/obstruction or vitality/hormonal domains.
The EPIC-26 is a broadly accepted, user-friendly instrument that measures HRQOL concerns related to early prostate cancer. EPIC has been used to asses the impact of aging on domain-specific HRQOL 15
, satisfaction and regret with prostatectomy 16
, erectile dysfunction in patient treated with external beam radiation 17
and HRQOL among patients treated with bladder preservation therapy for muscle-invasive bladder cancer 18
. Having been successfully used in the field by several investigative teams suggests the EPIC has robust construct validity. Although EPIC-26 improves the ease of administration, the EPIC-50 remains valuable whenever there is a need to evaluate function as distinct from bother.
Our development and validation of EPIC-26 presented herein has limitations. The abbreviated EPIC-26 takes about 10 minutes to complete, and although this length is more practical for widespread research use than are longer versions, it may nevertheless be cumbersone to administer routinely in some clinical practice settings. Accordingly, in the next phase of refinement of the EPIC instrument we plan to explore item reduction and format revision to facilitate ease of administration further; however, excessive item reduction can compromise reliability of a patient-report instrument. 8
Another potential limitation of this study was our use, for item reduction, of cohort data that had been collected some 10 years previously. Nevertheless, the contemporary relevance of EPIC-26 has been ascertained in a subsequent, contemporary, multi-center study, and ultimately a robust HRQOL instrument should retain relevance through an extended period of time, as exemplified by the SF-36 and other tools. 3
The EPIC-26 is a validated short form of EPIC-50 that has been effectively employed to follow long-term domain-specific changes in HRQOL among prostate cancer survivors in single-centre 19
and multi-institutional studies, 9
with the latter having been facilitated by availability of a telephone script for administration of EPIC-26 by phone survey or Computer-Assisted Telephone Interview (CATI). In practice, the EPIC-26 instrument is completed quickly, taking 10-15 minutes to administer 9
, making it a comprehensive and practical tool for use in research and making it less onerous than the 50-item EPIC for use either in combination with other patient-report instruments or for efficient administration in routine clinical practice.