Stratification of postprostatectomy urinary function using expanded prostate cancer index composite

To classify the Expanded Prostate Cancer Index Composite (EPIC)-Short Form urinary domain (EPIC-UIN) scores, as part of a validated health-related quality of life instrument after prostate cancer treatment into clinically meaningful functional categories.

Using a prospectively maintained database, approved by the institutional review board, of patients undergoing prostatectomy for malignancy, the patient and tumor factors and validated health-related quality of life instruments, including EPIC-UIN and the Incontinence Severity Index (ISI) were retrospectively reviewed. The questionnaires were completed preoperatively, at 3, 6, 9, and 12 months postoperatively, and yearly thereafter. Cutpoints were chosen for the EPIC-UIN scores to correlate with ISI, and statistical analysis querying this correlation was performed.

A total of 446 patients completing 764 questionnaires were reviewed. On average, the patients were 59.2 years old with a Gleason score of 6.75. All patients underwent robotic-assisted (n=224) or radical retropubic (n=222) prostatectomy. The range of ISI scores at the prescribed measurement points was "mild" (0-6), "moderate" (7-16), and "severe" (≥17) in 58.9%, 28.9%, and 11.3% of patients, respectively. An EPIC-UIN score of 0-49, 50-69, and 70-100 was chosen to correlate with the ISI score of "severe," "moderate," and "mild," with an agreement of 74.1% (weighted kappa coefficient 0.6541). Severe incontinence and moderate incontinence on the EPIC-UIN were associated with a sensitivity of 74% and 90.6% and specificity of 90.2% and 93.6%, respectively.

Categorical EPIC-UIN groups were developed to represent the mild, moderate, and severe incontinence. These categories provided meaningful guides for assessing postoperative urinary incontinence and recovery of urinary function.