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What Happens During Radiation Therapy for Stomach Cancer

You can receive radiation treatment as an outpatient in a hospital or a clinic. You usually receive treatment five days a week. The treatment continues for six to 12 weeks, depending on the type and dose of radiation recommended by your radiation oncologist.

Preparing for radiation treatment

Before your first radiation treatment, you’ll have an appointment to plan exactly where on your body the radiation beam needs to be directed. This process is called simulation. The appointment may take up to two hours. Here’s what you can expect to happen during simulation:

  • You’ll lie still on a table while a radiation therapist uses a machine to define your treatment areas. These areas may be called treatment fields or treatment ports. The field is the exact area on your body where the radiation will be aimed. You may have more than one treatment field if you have cancer in more than one place. The therapist marks your skin with tiny dots of colored permanent ink tattoos so the radiation will be aimed at the exact same place each time.

  • You may also have imaging scans, such as CT scans, to help the doctors know the exact location of your tumor to better aim the radiation.

  • Depending on the type of radiation therapy you have, you may need to have a plastic mold of your body made to help you lie still during the treatment.

On the days you get radiation

Radiation therapy for stomach cancer usually comes from a machine called a linear accelerator. It’s called external beam radiation therapy (EBRT). There are two kinds of EBRT used to treat stomach cancer.

  • Standard EBRT. This type directs radiation at your stomach from one direction. You lie on a table while the machine is placed over you. The experience is much like getting an X-ray, only it lasts longer. You receive radiation for only about five minutes, but the whole process takes about 30 minutes. You’ll usually receive this treatment for seven or eight weeks.

  • Conformal EBRT. This newer type of EBRT directs radiation at your stomach from several directions. This type may be best for you if you have an advanced stage of cancer. Stage III or IV is considered advanced. Some types of conformal EBRT use higher doses of radiation for shorter periods of time. Other types use protons instead of radiation. Both of these reduce the damage to healthy tissue. Each treatment only lasts a few minutes. You receive this treatment for a number of weeks depending on your specific treatment.

Before having EBRT, you may need to have a lymph node biopsy to see if the cancer has spread outside your stomach. Doctors usually do this using laparoscopy. You’ll have a small incision in your abdomen.  The doctor places a tool called a laparoscope through the cut. The laparoscope lets the doctor look inside your body. The doctor can pass special instruments through the laparoscope to remove lymph nodes. Lymph nodes go to a pathologist, who examines them to see if they contain cancer.


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