Abstract: PD47-01
Sources of Funding: This work was supported by the National Cancer Institute at the National Institutes of Health (5T32CA106183 to M.D.T.); by the American Cancer Society (MSRG-15-103-01-CPHPS to M.J.R.); by the US Agency for Healthcare Research and Quality (1R01HS019356, 1R01HS022640-01); and through a contract from the Patient-Centered Outcomes Research Institute. No conflicts of interest.

Introduction

Disease severity may modulate the effects of prostate cancer treatment on patient-reported functional outcomes. The objective of this study is to determine how the effects of contemporary prostate cancer treatments on functional outcomes vary by disease risk.

Methods

The Comparative Effectiveness Analysis of Surgery and Radiation (CEASAR) study is a prospective, population-based, observational study which enrolled men with localized prostate cancer in 2011 and 2012. Patient-reported function was measured using the 26-item Expanded Prostate Index Composite (EPIC) at baseline, 6, 12, and 36 months after treatment. To identify differences in the effect of treatment on EPIC domain scores by disease risk, we fit a set of longitudinal models with interactions between disease risk and treatment type (radical prostatectomy [RP] or external beam radiotherapy [EBRT]) with adjustments for the following factors: time since treatment, pre-treatment function, age, race, comorbidity, educational attainment, insurance type, employment, marital status, physical function score, social support, depression score, participatory decision-making score, and study site.

Results

Among the 2544 participants, 1144 (45%) had low-risk, 983 (39%) had intermediate-risk, and 417 (16%) had high-risk disease. Among low-risk patients, RP causes more severe decreases in sexual function compared to EBRT at 3 years (mean difference in EPIC score: -14.30 [95% CI: -18.56, -10.53]); however, among high-risk patients, this difference becomes both clinically and statistically insignificant (-4.46 [-9.79, 0.88]). With respect to incontinence, RP leads to even greater declines in function among high-risk patients compared to EBRT at 3 years (difference in treatment effects among low risk: -14.60 [-18.00, -11.19] and high risk: -19.25 [-23.87, -14.62]). No clinically significant interactions between treatment and risk were detected among the bowel, hormone, or urinary irritative domains.

Conclusions

These data suggest that the effect of treatment on urinary incontinence and sexual function vary by disease risk. Namely, high-risk patients report similar sexual function at 3 years regardless of treatment type but more drastic declines in urinary incontinence after surgery.

Funding

This work was supported by the National Cancer Institute at the National Institutes of Health (5T32CA106183 to M.D.T.); by the American Cancer Society (MSRG-15-103-01-CPHPS to M.J.R.); by the US Agency for Healthcare Research and Quality (1R01HS019356, 1R01HS022640-01); and through a contract from the Patient-Centered Outcomes Research Institute. No conflicts of interest.