Erectile dysfunction (ED) is a common side effect of prostate cancer treatment. Existing medical treatment focuses on early penile rehabilitation, aiming to prevent penile shrinkage and preserve nerves and smooth muscles to facilitate erection return. It typically includes administration of phosphodiesterase type 5 inhibitor (PDE-5), application of vacuum constriction devices (VCD) or intracavernous injection immediately after prostate cancer treatment.
To evaluate the proposed intervention, a randomized, controlled longitudinal clinical trial will be conducted to examine the effect of this cognitive-behavioral intervention on early-stage prostate cancer patients with ED and their partners. The proposed study includes a pilot study, a randomized clinical trial (the main study) and data analysis. The study duration for main study participants is 10 months including one month of recruitment and baseline assessment, six months of intervention, and three months of follow-up. The study duration for pilot study participants is 7 months including one month of recruitment and baseline assessment plus six months of intervention.
The Pilot Study A pilot study will be conducted to develop and test the proposed study intervention over 12 months. The pilot study will recruit 36 early-stage prostate cancer patients and their partners. The 36 couples will be randomly assigned to three study arms: (1) standard medical treatment of ED (MED); (2) standard medical treatment of ED plus cognitive-behavioral intervention (MED+CBI); and (3) usual care (UC) in which the study participants will not receive any study intervention, but will continue with standard care that allows patient's request for ED treatment. The purpose to include the usual care group is to collect preliminary data to aid the estimation of intervention effect size, statistic power and sample size, and to compare the intervention outcome with the real world scenario in order to provide the justification for the inclusion or exclusion of the usual care arm in the main study. The pilot study participants will be assessed twice at baseline (T1) and 7 months (T2) only. Doppler Ultrasound of the penis will be performed at T1 and T2 to examine changes in the volume of penile blood flow in patients. Subjects are allowed to opt out of the Doppler Ultrasound test, because this pilot data is exploratory and five or more ultrasound tests per group are sufficient. Collecting and analyzing blood samples will be performed at T1 and T2 and subjects are allowed to opt out of this test as well. The blood sample will be collected in order to test transforming growth factor beta-1 (TGF-ß1) and to assess its relation to erectile function. The result will allow us to evaluate the intervention impact at molecular level and formulate a best possible intervention to ED.
The Main Study During a 4-year clinical trial study, 144 early-stage prostate cancer patients along with their partners will be randomly assigned to two study arms: (1) standard medical treatment of ED (MED) and (2) standard medical treatment of ED plus cognitive-behavioral intervention (MED+CBI). The MED includes administration of sildenafil citrate (Viagra) and/or vacuum constriction devices (pump). The MED+CBI entails six in-person sessions and five telephone follow-ups over six months. The patients will be assessed on erectile function (EF), quality of life (QOL) and mood at baseline (T1), 7 months (T2) and 10 months (T3). The partners will be assessed on QOL and mood at T1, T2 and T3. Doppler Ultrasound of the penis will be performed at T1 and T2 to examine changes in the volume of penile blood flow among 50 patients who will be consecutively selected from the two study groups, with 25 per study arm.
The long-term primary goals of the study are to:
1. Assess the effect of the new treatment on erection function, quality of life, and mood.
2. Assess the treatment compliance and frequency of sexual activity of the new treatment.
3. Investigate the mechanism in which the new treatment works.
The long-term secondary goals of the study are to:
1. Assess the effect of the new treatment on the quality of life and mood of the patient's partner.
2. Assess the changes in the volume of penile blood flow due to study treatments.
