PURPOSE: To expand the clinical usefulness of the Expanded Prostate Cancer Index Composite for Clinical Practice (EPIC-CP) by evaluating its responsiveness to health related quality of life (HRQOL) changes, defining the minimally important differences (MID) for an individual patient's change in each domain, and applying it to a sexual outcome prediction model.
METHODS: In 1,201 subjects from a previously described multi-center, longitudinal cohort, we modeled each treatment group's EPIC-CP domain scores at pre-treatment, short-term, and long-term follow-up. We considered post-treatment domain score changes from pre-treatment ≥ 0.5 standard deviations (SD) clinically significant and with a p-value ≤ 0.01 as statistically significant. We determined domain MIDs using the 0.5 pooled SD of the 2, 6, 12, and 24 month post-treatment changes from pre-treatment. We recalibrated an EPIC-CP-based nomogram model predicting 2-year post-prostatectomy functional erections from that developed using EPIC-26.
RESULTS: For every HRQOL domain, EPIC-CP was sensitive to similar post-treatment HRQOL changes over time as had been observed using EPIC-26. The EPIC-CP MIDs for changes in the urinary incontinence, urinary irritation/obstruction, bowel, sexual, and vitality/hormonal domains are 1.0, 1.3, 1.2, 1.6, and 1.0, respectively. The EPIC-CP-based sexual prediction model performs well (AUC=0.76) and shows robust agreement with its EPIC-26-based counterpart, with predicted probability differences between models of ≤ 10% for 95% of individuals and a mean difference of 0.0 (SD=0.05) across all individuals.
CONCLUSIONS: EPIC-CP is responsive to HRQOL changes during convalescence, and can be used to predict 2-year post-prostatectomy sexual outcomes. Its use can facilitate shared medical decision-making and patient-centered care.
Written by:
Chipman JJ, Sanda MG, Dunn RL, Wei JT, Litwin MS, Crociani CM, Regan MM, Chang P. Are you the author?
Department of Biostatistics and Computational Biology, Dana-Farber Cancer Institute, Boston, MA.
Reference: J Urol. 2013 Sep 24. pii: S0022-5347(13)05509-2.
doi: 10.1016/j.juro.2013.09.040
PubMed Abstract
PMID: 24076307
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