Many factors can influence men’s erectile function (EF) after seed brachytherapy, Australian and British researchers have reported.
Used to treat prostate cancer, seed brachytherapy involves placing small radioactive pellets (“seeds”) close to the cancer cells. It may be used alone or with other treatments.
Erectile dysfunction (ED) is common in men who have been treated for prostate cancer. Past studies have suggested better erectile function over a three to four year period among men treated with brachytherapy when compared to those who underwent radical prostatectomy and external beam radiotherapy. However, there was still more to learn about erectile function after brachytherapy, the authors noted.
Three hundred sixty-six men with a mean age of 62 (range 42 to 80 years) participated in the study. All of the men had localized prostate cancer and were treated with seed brachytherapy alone. The participants had no (76%) or mild (24%) ED before treatment, based on International Index of Erectile Function (IIEF) scores. (The IIEF is a standardized tool commonly used to assess erectile function.)
The researchers followed up with the men for a median of 41 months, during which the IIEF was again administered.
Overall, the 5-year actuarial rate of EF preservation was 59% after treatment. This rate reflected the number of men who had “no worse than mild ED.”
However, certain factors influenced how well EF was preserved.
Age was one factor. The rate for men who were age 60 or older at treatment was only 50%, compared to a rate of 69% for men younger than 60.
Comorbidities were also important. Men who had conditions like hypertension, diabetes, and ischemic heart disease had a preservation rate of 47%. The rate for men without comorbidities was 64%.
The aggressiveness of the cancer was another factor. Men with a Gleason score below 7 (less aggressive cancer) had a EF preservation rate of 73%. Only 18% of men with a Gleason score of 7 had preserved erectile function.
Finally, rates were influenced by biologically effective doses of radiation. Men who received less than 150 Gy had an EF preservation rate of 74%, compared to 52% for men who received 150 Gy or more.
“In our analysis, we showed that EF preservation post-[seed brachytherapy] is multifactorial, and was influenced by a combination of patient-, tumor-, and treatment-related factors,” the authors noted.
They added, “It will be interesting to investigate the EF preservation over a longer follow-up period in future studies.”
Their research is currently an article in press, first published online in July in Radiotherapy and Oncology.
Radiotherapy and Oncology
Ong, Well Loon, et al.
“Long-term erectile function following permanent seed brachytherapy treatment for localized prostate cancer”
(Full-text. Article in press. Published online: July 30, 2014)