Impact of Pelvic Radiation Therapy on Inflatable Penile Prosthesis Reoperation Rates
Ron Golan MD; Neal A. Patel MD; Tianyi Sun MS; Christopher E. Barbieri MD, PhD; Art Sedrakyan MD, PhD; James A. Kashanian MD
FIRST PUBLISHED: November 2018 – The Journal of Sexual Medicine
DOI: https://doi.org/10.1016/j.jsxm.2018.09.009
Introduction
Radical prostatectomy (RP) and radiation therapy (RT) are two common treatments for prostate cancer. After either treatment, most men experience some degree of erectile dysfunction (ED), which can negatively affect their quality of life.
ED treatments may include phosphodiesterase type 5 (PDE5) inhibitors, vacuum-constriction devices, and injection therapy. If these approaches are not successful, the implantation of an inflatable penile prosthesis (IPP) is usually the next step.
Some urologists are reluctant to perform IPP implantation after RT because damage to soft tissue and impaired wound healing may increase the risk of infection or erosion. Such proinflammatory effects can take place immediately after radiation and later on. Also, men have had poor results with other urologic prosthetics after RT, according to past research.
The goal of the current study was to determine whether men who undergo prosthesis implantation after RT have greater reoperation rates than men who receive their IPP after RP.
Methods
The Surveillance, Epidemiology, and End Results (SEER)-Medicare Database was used to identify men who had been previously diagnosed with localized prostate cancer from 2002 to 2013, had been treated with either RP or RT, and had undergone IPP insertion. Men who had had adjuvant or salvage therapy (RT and RP) were excluded, as were men who had received an artificial urinary sphincter.
The primary outcome was reoperation, defined as the first procedure (removal, revision, or replacement) after IPP insertion based on RT or RP. The association between time from RT or RP to IPP implantation and risk of reoperation were also considered.
Results
Three hundred fifty men (median age 71 years) received an IPP after RT, and 653 men (median age 74 years) underwent IPP insertion after RP. The median follow-up time for both cohorts was 50 months. Comorbidities, including hypertension, diabetes, coronary artery disease, peripheral vascular disease, and chronic kidney disease, were more common in the RT group.
Overall reoperation rates were as follows:
| 90 days | 1 year | 3 years | |
| RT Group | 4.9% | 8.6% | 13.1% |
| RP Group | 5.4% | 7.3% | 11.1% |
These reoperation rates between the groups were not statistically different at any time point.
The rates were similar to reoperation rates in previous studies, which ranged from 7.4% to 12.0%.
Mechanical failure prompted reoperation for 58% of the men in the RT group and 64% of the men in the RP group. Infection diagnoses were similar for the two groups (sample size not reportable).
An adjusted time-to-event analysis was conducted. Compared to RP, RT was not associated with an increased likelihood of overall reoperation, removal, or revision. The median time to reoperation was 7 months for the RT cohort and 6 months for the RP cohort.
The median time between RT and IPP insertion was 31 months. Time between procedures was not associated with reoperation rates at any of the reported time periods.
Discussion
Men who receive prior radiation therapy for localized prostate cancer are not at higher risk for IPP reoperation or removal compared to men who undergo radical prostatectomy. There were no significant differences in operation rates, despite the RT group’s older age and greater likelihood of comorbidities.
Time between RT and IPP insertion did not appear to impact reoperation rates. “Early consideration of IPP following the completion of RT can be considered safe,” the authors wrote.
They added that the results must be viewed with caution based on their study design. While the studied outcome was reoperation, it was not known whether surgeons used technical modifications or found technical difficulties during surgery. Surgeons’ experience with IPP procedures was also not known.
“IPPs should be offered as a safe and effective treatment option for men with medication-refractory ED,” they concluded.