Intensity-modulated radiation therapy (IMRT) is the most common type of external beam radiation therapy (EBRT). IMRT is a more targeted treatment than other types of EBRT.
EBRT is a treatment used for prostate cancer. During this treatment, an X-ray machine emits high energy rays directly at the site of the tumor.
If you and your doctor are considering radiation therapy to treat your prostate cancer, you may want to consider the following information and discuss it with them, including the potential benefits and risks of IMRT.
IMRT treats prostate cancer via a machine that moves around your body as it emits radiation to certain areas of the body, which your doctor will have taken images of ahead of time. Like other types of EBRT, IMRT relies on 3D imaging of tumors so that the radiation will match the shape of the tumors.
However, unlike other types of EBRT, IMRT delivers more targeted radiation from various angles. Plus, the technician can adjust the intensity levels of the radiation used. This means that more radiation can be delivered to prostate tumors while protecting nearby tissues.
IMRT also uses hypofractionated radiation, which uses larger doses of energy compared with traditional radiotherapy.
Due to its precision and intensity control, IMRT is considered an effective form of radiotherapy for early stage prostate cancer.
As one 2018 research review explains, IMRT is considered the standard form of EBRT used for prostate cancer due to its precise delivery of radiation and reduced radiation exposure to healthy organs.
Risks and side effects may include:
- diarrhea and other bowel issues
- rectal bleeding
- erectile dysfunction or impotence
- urinary concerns, such as incontinence or frequent urination
- fluid retention (lymphedema)
While some of these side effects are temporary and may develop within 2 weeks, others may worsen over time.
IMRT is performed at an outpatient center.
Before you begin treatment, you will first need to undergo marker placement in the prostate as well as simulation. The goal is to make sure images of the tumor are mapped out correctly so that you receive radiation in the right places.
Likely, a mold will be made to ensure you are lying in the correct placement for the procedure.
You’ll be asked to stop taking blood-thinning medications at least 3 days before your marker placement. Before your simulation, a doctor may ask you to do an enema. They may also recommend dietary modifications to reduce bloating.
The process of undergoing IMRT for prostate cancer is similar to having an X-ray done. Here’s what you can expect:
- Once in the treatment room, you’ll be asked to undress from the waist down, but you will wear your shoes during the procedure.
- A therapist will have you lie down on the table in the exact same position you were in during the simulation, using the mold for assistance if one was created for you.
- You’ll be asked to lie completely still once the treatment begins.
- While you won’t feel pain, you may hear noises from the machine as it moves around your body.
- After a few minutes, the technician will shut off the machine and help you get up from the treatment table.
How long does IMRT therapy for prostate cancer take?
The procedure itself only takes a few minutes. Most of the appointment is spent setting up the machine and getting you in place. Expect this process to take 60–90 minutes each time, advise the experts at Memorial Sloan Kettering Cancer Center.
You may go home after your treatment.
To help minimize side effects, a medical professional may recommend that you:
- get plenty of sleep, and take short daytime naps if you need them
- bathe daily and keep your skin moisturized
- increase your fluid intake
- avoid alcohol, caffeine, and spicy foods
Private insurance companies and government programs, such as Medicare and Medicaid, may cover part of the costs. But it’s important to contact your provider in advance for details.
Radiation treatments may be used at varying stages and grades of prostate cancer. Below is a brief comparison between IMRT and other radiation therapies:
- Traditional radiation treatment: Traditional radiation therapy involves the use of high energy beams to kill cancer cells with 2D technology rather than 3D.
- Conventional EBRT: An external machine emits radiation, but it’s not as controlled or precise as in IMRT.
- MRI-guided radiation therapy: This method combines similar techniques as IMRT with the assistance of an MRI scan to take detailed pictures of the prostate and tumor.
- Image-guided radiation therapy (IGRT): This is a type of IMRT that uses imaging techniques for more precise treatments and fewer side effects.
- Volumetric modulated arc therapy (VMAT): Another type of IMRT, VMAT uses a machine that rotates quickly around the body to deliver radiation within minutes.
- Stereotactic body radiation therapy (SBRT): This type of EBRT treatment uses larger amounts of radiation in a shorter amount of time than IMRT. However, the side effects may be worse with this method.
- Proton therapy: This last type of EBRT uses protons instead of X-ray technology to target cancer and spare nearby tissues. It’s not clear whether this method is more effective than IMRT.
- Stereotactic radiosurgery (SRS): Using a combination of X-rays, protons, and gamma rays, SRS may be considered for prostate cancer that has spread.
- Brachytherapy: Also known as internal radiation therapy, this method involves implanting small radioactive pellets in the prostate gland. It’s sometimes combined with EBRT and is most effective for early stage, low grade prostate cancers.
- Radiopharmaceuticals: These consist of injectable medications containing radioactive elements and are most beneficial for prostate cancer that has spread.
Prostate cancer is a common but slow-growing type of cancer. IMRT is one possible treatment method that may be considered when this cancer is found in early stages.
Keep in mind that IMRT isn’t your only treatment option and that treating prostate cancer is highly individual. If you’re interested in IMRT, speak with your doctor about how it might benefit your own case.