One of the main side effects of prostate cancer treatment is erectile dysfunction (ED). This can happen if the nerves and blood vessels that control erections are injured by surgery or radiation. The erectile tissue inside the penis can also be injured by radiation. Plus, hormone therapy (called androgen deprivation therapy, or ADT) may also cause erectile dysfunction. For men that are sexually active, this is the most feared side effect. It’s true that most men will experience some decline in their function. However, there are many treatment options depending on how severe the ED is.

How Do Erections Work?

To understand erectile dysfunction and its treatments, it is important to understand how erections work. There are two “phases” of an erection — the filling and trapping phases.

The “filling phase” occurs when excitement causes blood flow to increase into arteries (blood vessels) in the penis. Once this begins, the blood fills the erectile tissue, which causes it to expand. This leads to fullness of the penis.

The “trapping phase” begins once erectile tissue expands enough to collapse (close off) veins that drain blood from the penis. When these two things happen, the penis can get and keep a full, hard erection.

What is Erectile Dysfunction?

Erectile dysfunction means not being able to get or keep an erection hard enough for sex. This may mean not being able to get an erection at all, not being able to get an erection hard enough for intercourse every time, or not being able to keep an erection long enough for penetration.

Erectile dysfunction can be a problem in the filling or trapping phases that occur during an erection. When there is a problem with filling, you usually notice you can’t get an erection at all or it takes a long time to get an erection.

However, if it is an issue with trapping the blood in the penis, then you will lose the erection before climaxing. This is called a venous leak. It is like having a nail in your tire — this means that no matter how much blood comes into the penis, it will leak out. If erectile dysfunction goes on for a long time, you may have penile shortening (the penis gets shorter).

Work Up for Erectile Dysfunction

When you see a urologist about your ED, he/she will need to completely understand your history of erectile dysfunction, including:

  • When it started (Was it before or after your treatment?)
  • The quality of your erections (How hard are they and how long do they last?)
  • What treatment options have you tried?

Your doctor also will give you a physical exam. Depending on your erectile function, they may order a penile doppler or ultrasound to diagnose which type of erectile dysfunction you have. Arterial insufficiency is the decrease of blood flow into the penis. A venous leak means the penis can’t store enough blood to keep an erection. Knowing which type you have will help decide which treatment options are best for you.


Erectile dysfunction after prostate cancer treatment, whether it is surgery, radiation and/or hormone therapy, is common. ED is also debilitating, and patients and doctors often don’t talk about it. Understanding how normal erections work is important to understand how erectile dysfunction happens after prostate cancer treatment. Remember, be sure to seek out a urology specialist who is well-versed in explaining, working up, and treating erectile dysfunction. This will help to make sure that you get the best care in restoring your sexual health.

Sherita A. King, MD
Sexual Medicine Specialized Urologist, Georgia Cancer Center, Augusta University, Augusta, GA, USA

Zachary Klaassen, MD, MSc
Urologic Oncologist, Georgia Cancer Center, Augusta University, Augusta, GA, USA