Radiation therapy uses high-energy beams of X-rays or particles to kill cancer cells or stop them from growing.

Radiation therapy can be used to treat some penile cancers. If you're not circumcised, you will need to be before radiation starts. That's because radiation causes swelling of the foreskin, which can lead to problems like irritation, sores, and infection.

Here are the most common reasons why your healthcare provider may recommend radiation therapy:

• To treat some early stage cancers. Radiation might be used instead of any surgery to treat small tumors in order to preserve the penis.
• To shrink the cancer before surgery. Radiation can be given along with chemotherapy to make the tumor easier to remove with less damage to the penis.
• As the main cancer treatment. Radiation might be used when surgery isn't a choice.
• To treat cancer after surgery has been done to the penis or lymph nodes . Radiation therapy might be used after surgery to try to kill any remaining cancer cells. It can help reduce the chance that the cancer will come back. The treatment may be directed at the penis and pelvic lymph nodes
• To slow cancer growth. In advanced penile cancer, radiation can help control tumor growth.
• To ease symptoms. Radiation can help shrink tumors that have spread to other parts of the body and can't be treated with surgery, such as bone, lymph nodes, or other organs.

To plan your entire treatment strategy, you will meet with a team of cancer specialists. This team might include a urologist, radiation oncologist, and medical oncologist.

Radiation therapy for penile cancer can be given in two ways:

• External beam radiation. The most common way to get radiation for penile cancer is from a large machine that focuses beams of radiation at the cancer. You often get external beam radiation on an outpatient basis in a hospital or clinic. This means you go home the same day. External beam radiation is usually given 5 days a week, Monday through Friday, for many weeks.
• Internal radiation (brachytherapy). For this treatment, you stay in the hospital and a source of radiation is put into or right next to the cancer. This can be done using hollow needles (also called catheters) that are put into the tumor on the penis during an operation. This is called interstitial radiation. Much less often, instead of needles going through the cancer, the radiation can be delivered using a plastic cylinder or mold that goes over the penis. The radiation is inside the mold.

A healthcare provider who specializes in cancer and radiation is called a radiation oncologist. This provider works with you and your urologist to figure out the kind of radiation you need. This provider also decides the dose and how long you need to get treatment.

Before your first external beam radiation treatment, you'll have an appointment called simulation. This process is needed to decide exactly where on your body the radiation beam needs to be aimed. During this session, you may have imaging tests, such as CT, MRI, or PET scans done. This helps the healthcare providers know exactly where the tumor is and where to aim the radiation. Also at this session, you may have body molds made. These molds will help put you in the same position every time and keep you from moving during treatment.

Then, you'll lie on a table while a radiation therapist uses an imaging machine to mark your treatment field. The field is the exact place on your body where the radiation will be aimed. Sometimes it's called your port. The therapist may mark your skin with tiny dots of semipermanent ink or tattoos. These marks help make sure the radiation is aimed at the exact same place each time.

External beam radiation is given 5 days a week for several weeks. On the days you get treatment, you'll lie on a table while the machine rotates around you. You may have to wear a hospital gown. It's a lot like getting an X-ray, but it takes longer, about 15 to 30 minutes. You should plan on being there for about an hour.

At the start of each external radiation treatment session, a radiation therapist helps you get into position and may put blocks or special shields on you. These protect parts of your body from being exposed to radiation. The therapist then lines up lights on the machine with the marks on your skin so the radiation is directed to the right spot. The therapists may also take some images on the treatment machine to further make sure that you are lined up correctly. When you're ready, the therapist leaves the room and turns the machine on. You may hear whirring or clicking noises while the radiation is being given. The machine won't touch you. During the session, you'll be able to talk to and hear the therapist over an intercom. You can't feel radiation, so the process will be painless. You will not be radioactive afterward.

Internal radiation therapy is usually given over several days while you're in the hospital.

Because radiation affects normal cells as well as cancer cells, you may have some side effects. The side effects from radiation are usually limited to the area being treated. Some people have few or no side effects. If you do have them, your healthcare provider may change the dose of your radiation or how often you get treatment. Or treatment may be stopped until the side effects get better. Be sure to tell your healthcare provider about any side effects right away. It's important to treat them before they get worse.

These are some of the possible side effects of radiation to the penis:

• Skin irritation or changes in skin that gets radiation. These can range from redness to skin peeling or oozing.
• Burning during urination
• Problems urinating (If you can't urinate for several hours, it can be an emergency. Call your healthcare provider right away.)
• Permanent problems getting and maintaining erections
• Diarrhea and nausea

If radiation is aimed at nearby lymph nodes, side effects can include:

• Feeling tired
• Peeling of the skin in the groin region
• Nausea
• Diarrhea
• Fluid buildup in the groin or your legs (lymphedema) that may not go away if it's not treated right away
• Rarely, irritation or damage to the underlying bowel that causes a blockage (obstruction), which may need to be repaired with surgery
• You may have radiation reaching the testicles and causing damage that can result in low testosterone, low sperm counts, or even infertility

Most side effects tend to go away over time after you stop treatment. Still, if you have any of these side effects, talk with your healthcare provider about how to deal with them. Also discuss with your provider what side effects you may experience in the long term. What should you do if they become serious? Make sure you know what number to call with questions or problems. Is there a different number for evenings, holidays, and weekends?