ED Causes - Radiation Therapy

How does radiation therapy cause ED?

Radiation therapy is a well-known cause of ED. Radiation therapy uses high levels of radiation to damage cancer cells' DNA in an effort to destroy them or keep them from growing and dividing, while minimizing damage to the surrounding healthy cells. Both pelvic external beam radiotherapy and seed implants (brachytherapy) are used to treat prostate cancer.

Radiation therapy in the pelvis area of men can cause ED in 3 possible ways:

  • Arterial damage may block blood flow and/or damage the lining of the blood vessels that carry blood to the penis
  • Nerves in the pelvic area may become permanently damaged
  • Erectile tissue may be damaged, reducing blood flow to the penis and/or causing leakage of blood from erectile tissue (venous leak) during an erection

Some of the sexual side effects after radiation therapy are:

  • Inability to achieve or maintain an erection (erectile dysfunction)
  • Weaker, less satisfying orgasms
  • Pain during ejaculation (although this usually goes away within several weeks)
  • Dry orgasm or retrograde ejaculation (orgasm without the discharge of semen)
  • Less semen ejaculated

There are three main factors that determine the extent of vascular damage that occurs following radiation exposure:

  • Dose of radiation
  • The higher the dose the greater the degree of vascular damage
  • The amount of area exposed to radiation; the wider the area exposed, the more significant the damage
  • The existence of vascular risk factors

How common is it for men to experience ED following radiation therapy?

Radiation therapy is a well-known cause of ED. Although ED may begin about six months after treatment, and progress gradually, it is the most common long-term complication of radiation therapy.

There is a 20 - 80% chance of ED from radiation therapy. There seems to be an increase in sexual dysfunction rates as time goes by following radiation therapy. One study revealed that two years after radiation therapy, 61.5% of men reported they had ED.

Other predictors of ED can include patient age, pre-treatment erectile function, method and dose of radiation delivery, the use of neoadjuvant (pre-surgery) hormone deprivation and the duration following radiation at which the patient is assessed by a physician. Also, men who smoke or who have a history of heart disease, high blood pressure or diabetes also may be at a higher risk of ED. These conditions may have already caused some artery damage which becomes further damaged by the radiation, Older men (especially those over 60) may find that treatment accelerates the sexual side effects associated with normal aging.

Radiation specialists have developed new techniques that target just the prostate and avoid surrounding tissue, nerves and blood vessels essential in erectile function.

How soon after having radiation therapy are men likely to have ED?

Even with the most precise radiation therapy, men may experience some ED for the first few months after treatment. Many of the sexual side effects of radiation are slow and gradual, and may take as long as six months to several years to appear. Unfortunately, radiation-induced ED is usually permanent.

Does anti-androgen therapy make ED either better or worse?

Hormone treatment (also called androgen deprivation therapy or androgen suppression therapy) for prostate cancer attempts to stop, block or remove the production of testosterone and all androgens to slow down or stop the progression of cancer. When hormone therapy is used, it is common for sexual problems to occur within the month following the beginning of therapy.10 In addition to causing ED, hormone therapy can also reduce a man’s sex drive.

Other common sexual side effects with hormone treatment include:

  • Inability to get or keep an erection (ED)
  • Difficulty climaxing
  • Orgasm without discharge of semen (dry orgasm)
  • Weaker, less satisfying orgasms

Younger men tend to have fewer side effects from hormone therapy.