Radiation Therapy for Prostate Cancer
July 1, 2024
This page was reviewed under our medical and editorial policy by Jeffrey Y.C. Wong, M.D., professor, Department of Radiation Oncology, City of Hope® Cancer Center Duarte, and Percy Lee, M.D., professor, Department of Radiation Oncology, City of Hope Orange County Lennar Foundation Cancer Center
If radiation therapy is part of the patient's prostate cancer treatment plan, it's a good idea to understand the options the care team may discuss.
What Is Radiation Treatment for Prostate Cancer?
Radiation therapy is a treatment option that uses high-powered radiation to destroy cancer cells. It may be used as part of the patient’s prostate cancer treatment regimen in circumstances such as those listed below.
As a first line treatment: For patients with early-stage prostate cancers, the care team may recommend radiation therapy instead of more invasive procedures, such as surgery.
After surgery: The care team may recommend radiation therapy after surgeries such as prostatectomy to ensure that all cancer cells have been destroyed. They may also use radiation therapy if the cancer recurs (comes back) following surgery.
To treat advanced cancer: If stage 4 prostate cancer spreads to other areas, the care team may recommend using radiation therapy to keep it from spreading further and for symptom relief.
Types of Radiation Therapy for Prostate Cancer
External Beam Radiation Therapy (EBRT)
External beam radiation therapy uses radiation beams that are directed at the patient's tumor from outside the body to destroy cancer cells.
EBRT is typically performed five days a week for several weeks, but the care team will determine what is best for the patient to provide maximum radiation to the prostate cancer while reducing radiation to the nearby bladder, bowel and rectum.
The care team may use image-guided intensity-modulated radiotherapy (IG-IMRT). This technology allows the care team to create a three-dimensional map of the patient’s prostate so they can more precisely target the cancer.
Intensity Modulated Radiation Therapy (IMRT)
IG-IMRT is the most common form of external beam radiotherapy and has replaced three-dimensional conformal radiation therapy (3D-CRT) in most instances. IG-IMRT has at least two significant advantages over 3D-CRT.
First, it uses finer millimeter pencil beamlets of radiation, resulting in radiation therapy being much more confined to the prostate gland and significantly reducing side effects and risk.
Second, the IG-IMRT treatment machine has built-in CT imaging for every treatment to account for daily motion of the prostate gland and to ensure the radiotherapy is on target.
Brachytherapy
Brachytherapy, also called internal radiation therapy, allows the care team to place small seeds of radioactive material inside the patient's body to directly attack the tumor. The care team may perform a magnetic resonance imaging (MRI) scan of the patient's prostate to better determine whether he may be a good candidate for brachytherapy.
Side Effects of Radiation Therapy for Prostate Cancer
Side effects are possible following both EBRT and brachytherapy. Talk to the care team about whether supportive therapies are available to help manage these side effects.
Side Effects of EBRT for Prostate Cancer
Because the prostate is located close to the bladder and bowel, patients may experience side effects in these parts of the body, including:
- Diarrhea
- Erectile dysfunction
- Fatigue
- Hemorrhoids
- Lymphedema (swelling in the legs or genital area)
- Skin issues, such as a rash or redness
- Rectal bleeding
- Rectal soreness
- Urinary changes
Side Effects of Brachytherapy for Prostate Cancer
Some patients experience rectal pain, burning sensations or diarrhea due to a condition called radiation proctitis, which is caused by irritation due to the internal radiation therapy. Other brachytherapy side effects may include:
- Bowel changes
- Erectile dysfunction
- Urinary changes
Radiation After Prostatectomy
Following prostatectomy, radiation therapy may be given postoperatively if certain features are seen in the pathology specimen. More commonly, radiation therapy is given for patients who show rises in the prostate-specific antigen (PSA) level during follow-up with their urologists.
Patients are treated using image-guided, intensity-modulated radiation therapy (IG-IMRT), which typically lasts for approximately eight weeks, Monday-Friday. Harnessing the imaging platforms, patients typically receive an MRI in addition to traditional CT scanning for treatment planning. In some cases, the MRI may detect disease in the prostate bed that may otherwise have gone unnoticed, allowing the radiation oncologist to potentially give additional doses to these areas.