The prostate is not necessary for erections to occur. It adds secretions to the ejaculate, which help the sperm to survive. However it does not control the ability to have an erection.
Nevertheless, structures that are important to erectile function lie close to the prostate and can be damaged when the prostate cancer is treated. A series of fine nerves which, when active, trigger an erection, lie in bundles just next to the prostate. During sexual arousal, small blood vessels expand in order to deliver enough blood to increase the pressure in the cylinders within the penis.

Prostate cancer treatment such as radiotherapy or radical prostatectomy can damage both nerves and blood vessels near the prostate.

It is not necessary to achieve erection or penetration in order to achieve orgasm!  Natural erections can improve for up to 4 years after a radical prostatectomy.

What happens after a radical prostatectomy?

This operation removes the prostate and seminal vesicles. Initially the focus is on urinary control (continence), as the nerves and muscles that help control urination also lie close to the prostate, and can be affected.

Erections

A man will normally lose the capacity to have erections immediately after the operation, however with time (several months), there is usually some return of erection strength.
In part, the return of erections depends on the extent to which the nerves that lie close to the prostate could be spared during surgery. This in turn depends on how far the cancer extends into this area and is a choice that the surgeon can make only at the time of surgery. To spare the nerves and also leave cancer behind would defeat the purpose of the operation. If it is considered safe to do so, nerve sparing (preserving) techniques are usually used to avoid damaging these nerves.

It is helpful to use oral medications (taken by mouth) such as Viagra, Cialis or Levitra and/or penile injections to cause erections early after the operation (within days or weeks). This keeps the erectile tissue working and hastens the return of unassisted erections. Some men are advised to take these tablets in low doses prior to surgery, but this is not widely recommended yet.

You may be advised by your doctor to ‘give it time’. After surgery your body needs time to heal. Erections may return gradually. The strength of the erection you may have 4 months after surgery is not necessarily the same as the one you’ll have 2 years later. Many men experience improved natural erections over time with continued improvement reported for up to 3 years postoperatively.

After a radical prostatectomy, the stimuli that caused an erection in the past may not be as effective. Different types of stimulation may be needed. Visual stimulation may not be as important as direct (hands on) stimulation of the penis. No damage to the operation site can be done through experimenting. If you have a partial erection, go ahead and attempt intercourse – vaginal stimulation may encourage further and better quality erections. Continue with sexual relations even though erections may not occur. Don’t wait for the time when they ‘just happen’.

Dry ejaculation

After the operation, because the prostate and surrounding structures have been removed, at ejaculation, you don’t usually produce any ejaculation fluid. This is called a ‘dry ejaculation’. It is possible that some urine will be lost during an ejaculation sensation, but it is not harmful.

Shortening of the penis

When there is less stimulation of the penis and the nerves and blood vessels are not working as well as before the operation, the penis appears shorter in its flaccid (floppy) state. This can be distressing to some men. As recovery progresses, the penis will usually start to look more as it did before the operation. Nevertheless, it is generally accepted that in the erect state, the penis is about 10% shorter in the long term, and this can be a concern for some men. The penis appears ‘retracted’ into the body. This can be exaggerated if there is significant weight gain.

What happens after radiotherapy?

After radiotherapy, sexual function is not usually affected in the short to medium term. Several years after radiotherapy, erectile function typically declines gradually. This is thought to be due to the progressive damage to the nerves and small blood vessels near the prostate that are important for erections. It is reported that brachytherapy to control prostate cancer has a lower risk of erectile dysfunction when compared to external beam radiotherapy (see Mr PHIP No. 3) or surgery. Intensity modulated radiotherapy is a newer technique that may reduce damage to healthy tissues adjacent to the prostate.

Remember also that ageing itself has a dampening effect on sexual function. Ejaculation fluid is often maintained after radiation treatment, but may diminish over time (usually a few years).

What happens after hormone therapy?

Control of prostate cancer using hormone treatment usually results in reduced testosterone and as a result, sex drive will be diminished for most men. However, continuation of simple physical expressions of love and concern between you and your partner can be very important in the ensuing years.