Because of the high incidence of post-radiation erectile dysfunction (ED), up to 72% after external-beam radiotherapy, this patient category represents a most difficult therapeutic challenge. Therefore, prevention of ED could be more effective than treatment. Tadalafil, a new phosphodiesterase type 5 inhibitor, has been recently introduced. No studies have investigated the efficacy of tadalafil in preventing ED in patients undergoing radiotherapy for prostate cancer. Efficacy of tadalafil can last up to 36 hours after intake. This will result in a prolonged and continuos enhancement of penile vascular responsiveness. This randomized, double-blind, placebo-controlled study has been designed to evaluate the efficacy of 20-mg of tadalafil administered for 12 months in maintaining erectile function of potent patients undergoing external-beam radiotherapy for prostate cancer.
Primary Outcome Measures:
- To assess the efficacy, and safety, of 20 mg tadalafil once every 2 days, in comparison with placebo, to maintain erectile function of patients undergoing external-beam radiotherapy for prostate cancer.
Secondary Outcome Measures:
- Erectile function defined as the sum of questions 3 and 4 of the IIEF questionnaire every 3 months till the end of the study (at 3-6-12-24 months).
- Erectile function domain of the IIEF, defined as the sum of questions 1-5, and 15 of the IIEF questionnaire, questions 2 and 3 of the Sexual Encounter Profile (SEP), and responses to the other questions of the IIEF, at 3-6-12-24 months after initiation
Estimated Enrollment: |
100 |
Study Start Date: |
October 2005 |
Study Completion Date: |
November 2005 |
It will be a double-blind, placebo-controlled, randomized trial. Patients scheduled for external-beam radiotherapy for prostate cancer will start using tadalafil 20 mg or placebo the first day of radiation. The blinded medication (active drug or placebo) has to be taken once every two days starting the day of the first radiation up to 12 months (52 weeks) after radiotherapy. The active drug or placebo may be taken at bedtime unrelated to sexual activity. In case of side effects the dose can be reduced to 10 mg. Erectile function will be assessed every 3 months up to 6 weeks (week 58) after discontinuation of drug treatment by using questions 3 and 4 of the International Index of Erectile Function (IIEF). Responders (maintained erectile function) are defined as having a combined score of >=8 for the IIEF questions 3 and 4.