Learning About Fiducial Markers and Rectal Spacers for Prostate Radiation Therapy

What are fiducial markers and rectal spacers for prostate radiation therapy?

Before you start radiation therapy to treat prostate cancer, you may have a procedure to place fiducial markers and a rectal spacer in the area around your prostate.

Fiducial markers

Fiducial markers are tiny pieces of metal that can be placed in or around your prostate. They can help make radiation therapy more accurate because they show up clearly on X-rays and other images. This makes them easier to target during radiation treatments.

The markers don’t need to be removed after therapy is done. They stay in your body and won’t cause you any harm.

Rectal spacers

Rectal spacers limit how much radiation goes to the rectum during radiation therapy. The rectum is the last part of your large intestine and sits behind the prostate. A spacer moves your rectum farther from your prostate. This helps protect the healthy tissues of your rectum from damage. It also allows the prostate to get a full dose of radiation to treat cancer.

There are a few types of rectal spacers. Some are made from a special gel or liquid that’s injected in between your rectum and prostate. Others use a small balloon filled with liquid.

The spacer will stay in place while you have your treatments. It gets absorbed by your body in about 3 to 6 months. So you don’t need to have a procedure to remove the spacer.

How do you prepare for the procedure?

Your doctor will give you instructions on how to prepare for the procedure. For example, you may have to:

• Stop taking blood thinners or NSAIDs (medicines to lower pain and inflammation). These medicines can raise your risk of bleeding.
• Use an enema to clean out your lower rectum. An enema uses a device to push fluid into your rectum to flush out stool. You can buy an enema kit at a pharmacy.
• Start taking antibiotics the day before to help prevent infection. You will get a prescription if you need to do this.
• Stop eating solid foods the night before the procedure, if your doctor tells you to.

What happens during the procedure?

You'll get anesthesia before the procedure. It may make you sleep. Or it may just numb the area. You will sit in a special chair with your legs resting in stirrups. During the procedure, your doctor uses ultrasound or a CT scan to help see the prostate and rectum.

To place the fiducial markers, your doctor will use a thin, hollow needle to insert the markers in or around your prostate.

To place the rectal spacer, your doctor may inject a water-based gel or liquid into the area between your prostate and rectum. Or the doctor may put in a balloon that's filled with liquid.

The procedure usually takes about 30 minutes to an hour.

What can you expect after the procedure?

You’ll be able to go home from the hospital or clinic the same day. Your doctor or nurse will make sure you are able to urinate before you leave. You’ll need someone to drive you home.

Most people can resume their normal activities the next day. But there are a few things to keep in mind while you recover.

• Avoid heavy lifting or strenuous exercise for a few days.
• Do not ride bikes, motorcycles, or horses for about 2 weeks.
• Take any antibiotics or other medicines as your doctor tells you to.

The rectal spacer might cause you to feel some pressure or fullness in your rectum. This should go away after a few days.

What are the risks and side effects?

The most common side effect is a small amount of blood in your stool or urine for a few days. Traces of blood may show up in your semen for a few weeks after the procedure.

Serious problems are rare, but they can happen. These include:

• Bleeding or infection.
• Swelling of the prostate, which can block the flow of urine (called acute urinary retention).
• An allergic reaction to a medicine.

When should you contact your doctor?

Contact your doctor right away if you:

• Have symptoms of an infection, like a fever, chills, or flu-like symptoms.
• See large amounts of blood in your urine, stool, or semen.
• Have severe pain.
• Cannot urinate at all.