Exploratory Decision-Tree Modeling of Data from the Randomized REACTT Trial of Tadalafil Versus Placebo to Predict Recovery of Erectile Function After Bilateral Nerve-Sparing Radical Prostatectomy

Abstract Background Understanding predictors for the recovery of erectile function (EF) after nerve-sparing radical prostatectomy (nsRP) might help clinicians and patients in preoperative counseling and expectation management of EF rehabilitation strategies. Objective To describe the effect of potential predictors on EF recovery after nsRP by post hoc decision-tree modeling of data from A Study of Tadalafil After Radical Prostatectomy (REACTT). Design, setting, and participants Randomized double-blind double-dummy placebo-controlled trial in 423 men aged Intervention Postsurgery 1:1:1 randomization to 9-mo double-blind treatment with tadalafil 5mg once a day (OaD), tadalafil 20mg on demand, or placebo, followed by a 6-wk drug-free-washout, and a 3-mo open-label tadalafil OaD treatment. Outcome measurements and statistical analysis Three decision-tree models, using the International Index of Erectile Function-Erectile Function (IIEF-EF) domain score at the end of double-blind treatment, washout, and open-label treatment as response variable. Each model evaluated the association between potential predictors: presurgery IIEF domain and IIEF single-item scores, surgical approach, nerve-sparing score (NSS), and postsurgery randomized treatment group. Results and limitations The first decision-tree model ( n =422, intention-to-treat population) identified high presurgery sexual desire (IIEF item 12: ≥3.5 and Conclusions Exploratory decision-tree analyses identified high presurgery sexual desire, confidence, and intercourse satisfaction as key predictors for EF recovery. Patients meeting these criteria might benefit the most from conserving surgery and early postsurgery EF rehabilitation. Strategies for improving EF after surgery should be discussed preoperatively with all patients; this information may support expectation management for functional recovery on an individual patient level. Patient summary Understanding how patient characteristics and different treatment options affect the recovery of erectile function (EF) after radical surgery for prostate cancer might help physicians select the optimal treatment for their patients. This analysis of data from a clinical trial suggested that high presurgery sexual desire, sexual confidence, and intercourse satisfaction are key factors predicting EF recovery. Patients meeting these criteria might benefit the most from conserving surgery (robot-assisted surgery, perfect nerve sparing) and postsurgery medical rehabilitation of EF. Trial registration ClinicalTrials.gov, NCT01026818