Prostate Cancer: Radiation Therapy

Medically Reviewed by Jennifer Robinson, MD on October 23, 2019

Radiation therapy, also called X-ray therapy, uses high levels of radiation to kill prostate cancer cells or keep them from growing and dividing, while minimizing damage to healthy cells.

Radiation can be produced from a machine outside the body (external radiation) and directed right at the prostate or by putting materials that produce radiation (radioisotopes) through thin plastic tubes into the cancer-infected area (internal radiation or brachytherapy).

Internal radiation therapy places radioactive implants directly into the tumor. These radioactive sources can be temporary (removed after the proper dose is reached) or permanent. See Radioactive Seed Implants for more about this type of radiation therapy for prostate cancer.

What Happens on Treatment Days?

External radiation therapy requires regular sessions (generally five days per weeks) during a period of about five to eight weeks. For each treatment, the radiation therapist will help you onto the treatment table and into the correct position. Once the therapist is sure you are positioned well, they will leave the room and start the radiation treatment.

You will be under constant observation during the treatment. Cameras and an intercom are in the treatment room, so the therapist can always see and hear you. Be sure to remain still and relaxed during treatment. Let the therapist know if you have any problems or discomfort.

The therapist will be in and out of the room to reposition the machine and change your position. The treatment machine will not touch you, and you will feel nothing during the treatment. Once the treatment is complete, the therapist will help you off the treatment table.

The radiation therapist will take a port film, also known as an X-ray, on the first day of treatment and about every week thereafter. Port films verify that you are being positioned accurately during your treatments.

Port films do not provide diagnostic information, so radiation therapists cannot learn about your progress from these films. However, port films are important to help the therapists make sure the radiation is delivered to the precise area that needs treatment.

Why Are There Marks on My Skin?

Small marks resembling freckles will be made on your skin along the treatment area by the radiation therapist. These marks provide targets for the treatment and are a semi-permanent outline of your treatment area. Do not try to wash these marks off or retouch them if they fade. The therapist will re-mark the treatment area when necessary.


Will My Diet Affect My Treatment?

Yes. Good nutrition is an important part of recovering from the side effects of radiation therapy. When you are eating well, you have the energy to do the activities you want to do, and your body is able to heal and fight infection. Most important, good nutrition can give you a sense of well-being.

Since eating when you don't feel well can be difficult, consider working with a dietitian. They can help make sure that you are getting adequate nutrition during your radiation therapy.

What Side Effects Will I Have?

During your treatment, radiation must pass through your skin. You may notice some skin changes in the area exposed to radiation. Your skin may become red, swollen, warm, and sensitive, as if you have a sunburn. It may peel or become moist and tender. Depending on the dose of radiation you receive, you may notice a loss of hair or decreased perspiration within the treated area.

These skin reactions are common and temporary. They will subside gradually within four to six weeks of completing treatment. If skin changes appear outside the treated area, inform your doctor or primary nurse.

Long-term side effects, which can last up to a year or longer after treatment, may include a slight darkening of the skin, enlarged pores, increased or decreased sensitivity of the skin, and a thickening of tissue or skin.

Another possible side effect is erectile dysfunction and urinary symptoms such as frequency, bleeding, or, rarely, incontinence. Keep these side effects in mind when considering your treatment options. If you have any concerns, don't hesitate to talk to your doctor about them.

How Can I Reduce Skin Reactions?

  • Gently cleanse the treated area using lukewarm water and a mild soap such as Ivory, Dove, Neutrogena, Basis, Castile, or Aveeno Oatmeal Soap. Do not rub. Pat your skin dry with a soft towel or use a hair dryer on a cool setting.
  • Try not to scratch or rub the treated area.
  • Do not apply any ointment, cream, lotion, or powder to the treated area unless your radiation oncologist or nurse has prescribed it.
  • Do not wear tight-fitting clothing or clothes made from harsh fabrics such as wool or corduroy. These fabrics can irritate the skin. Instead, choose clothes made from natural fibers such as cotton.
  • Do not apply medical tape or bandages to the treated area.
  • Do not expose the treated area to extreme heat or cold. Avoid using an electric heating pad, hot water bottle, or ice pack.
  • Do not expose the treated area to direct sunlight, as sun exposure may intensify your skin reaction and lead to severe sunburn. Choose a sunscreen of SPF 30 or higher. Protect the treated area from direct sunlight even after your course of treatment is over.


Will Radiation Therapy Make Me Tired?

Everyone have their own energy level, so radiation treatment will affect each person differently. Patients often feel fatigue after several weeks of treatment. For most patients, this fatigue is mild. However, a loss of energy may require some patients to change their daily routine.

If your doctor thinks you should limit your activity, they will discuss it with you.

To minimize fatigue while you are receiving radiation treatment:

  • Be sure to get enough rest.
  • Eat well-balanced, nutritious meals.
  • Pace your activities and plan frequent rest periods.

What is 3-D Conformal Radiation Therapy?

3-D conformal radiation therapy uses CT-based treatment (CT is short for computed tomography, which uses X-rays to produce detailed pictures inside the body) combined with three-dimensional images of a prostate tumor.

Radiation is aimed at the prostate gland from numerous directions, thus minimizing the damage to normal tissue. This technique allows for precise delivery of radiation doses. So far, it has worked well for localized tumors, such as prostate cancer limited to the prostate gland.

General Guidelines

  • All patients have a CT scan specifically for radiation therapy treatment and planning.
  • The CT data is electronically transferred to the 3-dimensional treatment planning computer.
  • The doctor defines the area to be treated along with surrounding areas, such as the bladder, rectum, bowel, and bones.
  • An optimal radiation beam and dose are analyzed using a 3-dimensional computer-generated model.
  • When the exact dose of radiation to the prostate is determined, the patient returns for a treatment simulation.
  • The simulation process transposes or maps the computer-generated plan to the patient. The doctor will review the treatment course and side effects with the patient.


Possible Side Effects

  • Hair loss may occur in the area being radiated.
  • Nausea and vomiting are uncommon unless the upper abdominal areas are radiated.
  • Mild fatigue. Patients continue their normal routine during their treatment, including working full time.
  • Frequent urination, a weak urine stream, or a mild burning with urination.
  • Diarrhea, though uncontrolled diarrhea is rare. Because the radiation beam passes through normal tissues, such as the rectum, bladder, and intestines on its way to the prostate, it kills some healthy cells. This is why diarrhea may result.
  • Possible long-term problems, including proctitis (inflammation of the rectum) with bleeding, bowel problems such as diarrhea, incontinence, and impotence.


What Is Intensity-Modulated Radiotherapy?

Intensity-Modulated Radiotherapy (IMRT) is an advanced approach to 3-D conformal radiation therapy. The IMRT technique is very precise.

IMRT uses computer-generated images to plan and then deliver tightly focused radiation beams to prostate cancer tumors. With this capability, clinicians can vary the beam intensity to "paint" a precise radiation dose to the shape and depth of the tumor, while significantly reducing the harmful effects of doses on healthy tissue. Clinical studies indicate that higher dose rates delivered with IMRT techniques improve the rate of local tumor control.

Other techniques that are being used or studied include:

  • Image-guided Radiation Therapy (IGRT) uses radiation machines with built-in scanners that allow for minor adjustments beforeradiation is given.
  • Volumetric Modulated Arc Therapy (VMAT) delivers radiation quickly while it rotates around the body.
  • Stereotactic Body Radiation Therapy (SBRT) uses advanced image-guided ways to deliver a large dose of radiation to a very specific place in the prostate. The entire treatment is usually done in just a few days.

What is Proton Beam Radiation Therapy?

Proton beam radiation therapy treats tumors with protons instead of X-ray radiation.  This therapy may be able to deliver more radiation specifically to a prostate cancer tumor with less damage to normal tissue.  Proton therapy is only available in certain centers in the U.S. 


Additional Questions About Radiation Therapy

Who Can I Contact If I Have Personal Concerns About My Treatment?

Many hospitals and clinics have a staff social worker who can help you during your treatment. Check with your doctor to see if this is available to you.

The social worker can discuss any emotional issues or other concerns about your treatment or your personal situation and provide information about resources. The social worker can also discuss housing or transportation needs if necessary.

People dealing with certain medical issues find it helpful to share experiences with others in the same situation. Your doctor can provide a list of support groups if you are interested. Your social worker can provide additional information, and you can look online for support group resources.

What About Follow-Up Care?

After your radiation therapy sessions are complete, you will visit your doctor for periodic follow-up exams and tests. Your doctor will tell you how often to schedule your follow-up appointments. You may be eligible to receive a Survivorship Care Plan outlining both what treatment you were given, what side effects may be expected in the short and long term, and who should be following you for what testing and care. Ask your doctor about it.