External Beam Radiation Therapy

In external beam radiation therapy, radiation is produced by a machine called a linear accelerator. Short bursts of x-rays are fired from the machine at your cancer. The x-rays come out in a square-shaped manner, and the radiation oncologist designs special blocks to shape the radiation beam so that it affects the cancer and as little normal tissue as possible.

Radiation of a Tumor

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Like ]]>chemotherapy]]>, the side effects from radiation result from injury to normal body tissues. There are many ways that a radiation oncologist can customize your treatment to try to kill as much cancer while sparing as much normal tissue as possible. The radiation oncologist will determine how many treatments you will receive; sometimes they will be once a day and sometimes twice per day. Each treatment generally only takes a few minutes, and the total treatment time can range from 5-8 weeks depending on the total dose required.

Radiation therapy can be given to treat cancer at its initial site or once it has spread. In some cases, once cancer has spread, radiation is no longer effective. However, the treatments can help resolve problems that the cancer may be causing, including pain and weakness.

Many people believe that once you have received a certain dose of radiation you can no longer get any more treatment. It is true that each tissue in the body can only safely tolerate a certain dose of radiation. However, the therapy is very focused. and it is possible that you can get additional treatments to an already treated area or certainly to an area not yet treated. Ask your radiation oncologist about what dose you can safely receive.

A type of external beam radiation therapy that may be used to treat ]]>ovarian cancer]]> is called whole abdominal radiotherapy (WART). Like chemotherapy, WART is designed to treat all of the tissues in your abdomen where ovarian cancer cells may be hiding after surgery. In the 1960s and 1970s, WART was commonly offered in the US. After a study in the mid-1970s showed that the side effects were worse after WART than after chemotherapy, chemotherapy became the more popular treatment in the US. WART is still used commonly throughout Europe and Canada, and several cancer centers in the US still use WART. Ask your doctor if this treatment is reasonable for you.

Radioactive P-32

In some rare cases, your doctor may ask you to consider a radioactive liquid called phosphorus 32 (P-32). The doctor will instill it into your abdomen and move it around so that it touches all the surfaces of the inside of your belly, where tumor cells could be hiding. This treatment is easy to perform, but it can cause nausea and vomiting, and it increases the chances that you could develop bowel complications later in life. Scientists are still debating whether radioactive P-32 helps beyond surgery and chemotherapy. Intraperitoneal radiation treatment is most often used after a “second look” surgery to consolidate treatment.

When to Contact Your Doctor

Call your doctor if you develop:

• Side effects from the treatment
• New or unusual symptoms, especially nausea, ]]>diarrhea]]>, vomiting, bleeding, or bruising
• Pain in the abdomen
• Red, blistered, or swollen skin