Radiation Therapy for Anal Cancer

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Meet Lillian Kreppel, who was successfully treated at MSK for stage II anal cancer and is working to raise awareness about this rare disease.
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Radiation therapy is the most common treatment for anal cancer. If your doctor recommends radiation, you may be worried about what treatment will entail. You may also be concerned about the possible side effects.

Radiation oncologists specialize in treating cancer with radiation. MSK’s radiation oncologists are some of the most experienced in the country. Our unmatched level of expertise means that you will receive the best care possible.

When you receive radiation for anal cancer at MSK, your care team will include dedicated radiation oncologists, nurses, therapists, and physicists, as well as a surgeon and other highly trained staff. We will work together to ensure you receive the safest, most effective treatment, and that all of your needs are met. We also use special techniques and provide support services to help you keep your quality of life.

Types of Radiation for Anal Cancer

There are several ways to treat anal cancer with radiation, including:

  • as the main treatment, so you don’t need surgery
  • in combination with chemotherapy
  • after surgery, to get rid of any remaining cancer cells
  • to relieve symptoms, such as pain

MSK’s radiation therapy team has access to the most advanced forms of radiation available. We have extensive knowledge about which approach will provide you with the most benefit. Our goal is twofold. We want to eliminate the cancer cells and prevent the side effects of treatment by keeping the healthy cells around the tumor safe.

Here you will find in-depth information about the types of radiation used to treat anal cancer.

Intensity-Modulated Radiation Therapy for Anal Cancer

Intensity-modulated radiation therapy (IMRT) is the most common type of radiation for anal cancer. It is a form of external-beam radiation. IMRT uses a highly advanced computer program so your care team can precisely shape the radiation beams to the dimensions of the treatment area.

Before treatment begins, expert radiation oncologists and medical physicists will collect detailed information about the treatment area. You will have:

  • a CT scan to map the tumor in 3-D
  • PET, CT, and MRI scans to identify the outline of the tumor

Your care team uses this information along with sophisticated treatment-planning software. With this program, we can calculate the right number of radiation beams and the specific angle of those beams. You may also receive chemotherapy to weaken the cancer cells before the radiation treatment. This helps the radiation be more effective.

This approach allows us to deliver more-precise doses of radiation to the tumor while protecting your nearby healthy tissue.

Proton Therapy for Anal Cancer

Proton therapy is a form of radiation that uses charged particles called protons. Conventional radiation uses X-rays. Proton therapy can reduce the likelihood of damage to healthy tissue because proton beams do not penetrate beyond the tumor. It also allows us to deliver higher doses of radiation, maximizing the chance of destroying the tumor

Using proton therapy to treat anal cancer is a relatively new approach. Doctors are still studying its benefits. Proton therapy is most commonly used to treat head and neck cancer and pediatric cancers.

Memorial Sloan Kettering is one of a limited number of centers nationwide to offer proton therapy. You and your doctor will discuss if you are a good candidate for this treatment. Currently, MSK patients receive proton therapy in Somerset, New Jersey.

Side Effects of Radiation Therapy for Anal Cancer

Some immediate side effects of radiation may include:

  • diarrhea and pain while going to the bathroom
  • burns or rashes on the skin at the treatment site
  • tiredness
  • nausea
  • vaginal irritation

Our radiation oncologists will talk with you in detail about what to expect from radiation. You will know when side effects are likely to appear. We can prescribe items to help keep you as comfortable as possible, like a topical cream or pain medication.

Most of these side effects go away after treatment ends. Other long-term side effects are possible, but our experts have developed techniques and support programs to help you deal with them.

  • Fertility: Radiation can affect fertility for both men and women. Our experts know that fertility is an important and very personal concern. We’ve developed ways to give you the best chance of preserving your fertility. Learn more about fertility preservation options.
  • Vaginal health: Radiation for anal cancer can cause damage to the vagina. You may have discomfort and pain. Memorial Sloan Kettering has an entire program dedicated to helping you maintain your vaginal and sexual health before, during, and after treatment. Using special devices while you receive radiation can help protect your vaginal health. Learn more about sexual health services.
  • Bowel function: Radiation to the anus can cause tissue damage. Eventually, this damage may lead to the formation of scar tissue. If this happens, it may impact how the muscles in the anus function. This may cause problems with bowel function and continence. Your care team may use special techniques or treatments to reduce or adapt to changes in bowel function.