We have been discussing the varying effects that the different treatment options for prostate cancer can have on erectile function. We will now discuss radiation therapy. There are several types of radiation therapy that can be administered.
Brachytherapy is the administration of radioactive “seeds” into the prostate. Much like cryotherapy, the seeds are placed into the prostate through the perineum (the area under the scrotum and above the anus). The “seeds” are small radioactive pellets that are smaller than a grain of rice. Ultrasound is used to guide the placement of the seeds evenly throughout the prostate gland. The ultrasound is placed into the rectum and the prostate is visualized in that way (much like how the prostate is felt when your doctor places his finger into the rectum). The regions where the nerves responsible for erection are thought to be located are avoided. The seeds are permanently implanted. Each seed gives off radiation to the prostate that kills the cancer cells.
Since the radiation kills or damages all cells in its pathway and cannot tell the difference between “good” cells and cancer cells, if the nerve structures are nearby, they may suffer some damage that could lead to erectile dysfunction. In the current literature the rate of erectile dysfunctions after brachytherapy is anywhere from twenty to forty-five percent. This means that those patients may experience worsening of their erections. That is not to say that they will never have another erection. It only means that there has been a reported worsening of the erections.
You may wonder also why there is such a large range in the percentage of ED. These numbers come from a large series of reports from multiple centers around the world. When we report these numbers, our definition (as urologists) of erectile function may vary. We are trying very hard to standardize this in our field, but the task is not trivial. The result of this can be confusing to the patient when they try to decide which treatment will be the best for them. It usually comes down to a calculation of which side effects the patient is more willing to deal with. Some doctors may define ED as the inability to penetrate the vagina with the penis. Other doctors may say that ED is the total lack of erection or any tumescence (hardening) at all, even with the use of erectile function aides (medicines, etc.). This all seems very subjective, and unfortunately, it is.
Another important reason for the variation could be related to the experience of the doctor or the medical center that is reporting the data. It seems logical that the more you perform a task, the better you may become. For example, a person who has been juggling for years will be better at it than someone who just picked up the balls for the first time. This could be another variation on why that number range is so large. Doctors that perform more, MAY (but not always) have better outcomes because of experience.