A randomized, controlled, three-arm study to define the utility of PDE5 inhibitors and intracavernosal injections in the radical prostatectomy population
Mulhall, J1; Kunzel, B1; Miranda, EP1; Nelson, C1
1: MSKCC, USA
Objective: The concept of penile rehabilitation post-radical prostatectomy (RP) has been around for almost 20 years. Yet, despite 3 randomized control trials, we have little definitive evidence regarding the utility intracavernosal injections (ICI) or which regimen is best for optimizing patient outcomes.
Methods: This IRB and FDA approved study studied penile rehabilitation in a three-arm fashion with a target enrollment of 200 patients. Arm 1: nightly placebo with sildenafil 100mgs on demand for sexual relations (up to 6 pills/month); Arm 2: nightly sildenafil 50mgs and sildenafil 100mgs on demand for sexual relations (up to 6 pills/month); Arm 3: nightly sildenafil 50mgs (5 nights/week) plus intracavernosal injections twice per week. Major inclusion criteria included: bilateral nerve sparing surgery, normal serum total testosterone and good baseline erectile function as measured by the erectile function domain score of the IIEF (≥24). Patients were followed with a medication use diary and the IIEF questionnaire at 6 weeks, 3m, 6m, 12m, 18m and 24m.
Results: 97 subjects were randomized: Arm 1, n=37; Arm 2, n=28; Arm 3, n=32. Mean age was 57±7 years, mean baseline EFD score 28±2. There were no differences in age, EFD score, or nerve sparing status at baseline. At 24m, the sample sizes by group were: Arm 1, n=11; Arm 2=27; Arm 3=17. Congruent with intent to treat analysis, we used the last observation carried forward. At 24m, the mean EFD scores were: Arm 1 15±8; Arm 2 22.8±8; Arm 3 19.1±8. There was no difference in mean EFD score between Arms 2 and 3 (p=0.16), thus they were combined to make a single ‘rehabilitation group’. When comparing Arm 1 to the ‘rehabilitation group’, the mean difference in EFD score at 24m in favor of the rehabilitation group was 6.4, p=0.03. When analyzing the highest EFD score carried forward, mean EFD scores were: Arm 1 16.5±9; Arm 2 23.5±7; Arm 3 24.4±7. When comparing Arm 1 to the ‘rehabilitation group’, the mean difference in EFD score in favor of the rehabilitation group was 7.3, p<0.01.
Conclusions: While the study struggled to complete enrollment, the data suggest that rehabilitation using either PDE5I or ICI is superior to an ‘on-demand’ approach.
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