Clinical Interpretation of the Expanded Prostate Cancer Index Composite-Short Form Sexual Summary Score

Purpose: The Expanded Prostate Cancer Index Composite is a validated health related quality of life instrument that is commonly administered after prostate cancer treatment. We classified Expanded Prostate Cancer Index Composite-Short Form sexual summary scores into clinically meaningful groups. Materials and Methods: A development cohort of 561 patients undergoing radical prostatectomy was used to define sexual summary groups by correlation with their responses on the Sexual Health Inventory for Men. A separate validation cohort of 430 patients was used to compare Expanded Prostate Cancer Index Composite-Long Form sexual bother scores among these sexual summary groups. Results: A sexual summary group score of 0 to 33, 34 to 45, 46 to 60, 61 to 75 and greater than 75 correlated with Sexual Health Inventory for Men groups of severe-1 to 7, moderate-8 to 11, mild/moderate-12 to 16, mild-17 to 21 and no erectile dysfunction-22 to 25, respectively. In the validation group mean sexual bother scores in each of the 5 sexual summary groups were significantly different from each other after controlling for patient age, stage, hormone treatment, marital status and nerve sparing (p <0.0001). Conclusions: Expanded Prostate Cancer Index Composite-Short Form sexual summary scores can be categorized into 5 groups for which excellent correlation is found with similar validated groups based on the Sexual Health Inventory for Men. Also, sexual bother scores are significantly different among the groups, showing that they represent discrete, clinically relevant cutoffs. This will help patients and physicians interpret Expanded Prostate Cancer Index Composite scores and help define potency for comparison among various prostate cancer treatments.