Radiation therapy for uterine cancer

Radiation therapy uses high-energy rays or particles to destroy cancer cells.

Some people with uterine cancer have radiation therapy. Your healthcare team will use what they know about the cancer and about your health to plan the type and amount of radiation, and when and how it is given.

You may have radiation therapy to:

• destroy cancer cells left behind after surgery or chemotherapy to reduce the risk that the cancer will come back (recur) (called adjuvant therapy)
• treat uterine cancer if you can’t have surgery
• relieve pain or control the symptoms of advanced uterine cancer (called palliative therapy)
• shrink a tumour before other treatments such as surgery or chemotherapy (called neoadjuvant therapy)

Radiation therapy and chemotherapy may be given during the same time period to treat uterine cancer. This is called chemoradiation. Some chemotherapy drugs can help make radiation work better by making cancer cells more sensitive to radiation. Combining chemotherapy and radiation therapy can be more effective than either treatment on its own.

The following types of radiation therapy are most commonly used to treat uterine cancer.

During external radiation therapy, a machine directs radiation through the skin to the tumour and some of the tissue around it. External radiation therapy is also called external beam radiation therapy.

External radiation therapy may be given on its own or together either with brachytherapy or systemic therapy, or both. Treatment with external radiation therapy is usually given 5 days a week, for 4 to 6 weeks. For advanced-stage uterine cancers, doctors may use a type of external radiation called intensity-modulated radiation therapy.

Intensity-modulated radiation therapy (IMRT) delivers radiation from many different angles to treat the entire tumour. In addition to shaping and aiming the radiation beams, IMRT allows the radiation oncologist to adjust the strength (intensity) of the individual beams. This reduces the dose of radiation reaching nearby normal tissue while allowing a higher dose to be delivered to the tumour. It’s useful for treating tumours in hard-to-reach areas.

Brachytherapy is a type of internal radiation therapy. A sealed container of a radioactive substance, called an implant, gets placed right into the tumour or in the area near where the tumour was removed. The radiation kills the cancer cells over time. Brachytherapy can be given on its own or together with either external radiation therapy or systemic therapy, or both.

Brachytherapy for uterine cancer may be given intracavitarily or interstitially. Intracavitary and interstitial brachytherapy are sometimes done at the same time.

Intracavitary brachytherapy gives radiation therapy through a cylinder filled with a radioactive substance (called the applicator) that is inserted into the body through the vagina. The applicator may remain in the vagina or be put into the uterus if you didn’t have a hysterectomy. Intracavitary brachytherapy is also called vaginal brachytherapy or vault brachytherapy.

Intracavitary brachytherapy is the most common type of brachytherapy given for uterine cancer.

Intracavitary brachytherapy may be given as a low-dose rate (LDR) or high-dose rate (HDR) treatment.

LDR brachytherapy delivers a lower dose of radiation over a longer period of time. A single LDR treatment can last between 1 and 4 days, during which the applicator or needles and obturator stay in your body. You will have to stay in the hospital for the duration of the LDR treatment. Most people will only have 1 LDR brachytherapy treatment.

HDR brachytherapy delivers a higher dose of radiation in a short period of time. The applicator or needles and obturator are placed in the vagina at the start and end of each HDR treatment. You usually don’t need to stay in the hospital overnight if you have HDR brachytherapy.

HDR brachytherapy is typically given once a week, for up to 3 weeks.

Interstitial brachytherapy gives radiation therapy through long, thin needles filled with a radioactive substance that are placed in the tissue to be treated. The needles are put into the walls of the uterus through your vulva, perineum (area between the vagina and anus), vaginal walls and other surrounding tissue. Interstitial brachytherapy can give a higher dose of radiation than vaginal brachytherapy. You are most likely to have it for recurrent uterine cancer. Interstitial brachytherapy may also be offered for uterine cancer if:

• the tumour is very large
• cancer has spread throughout the pelvis
• the applicator used for intracavitary brachytherapy doesn’t reach the area that needs treatment

Both intracavitary and interstitial brachytherapy are given under general anesthesia or neuraxial anesthesia.

During radiation therapy, your healthcare team protects healthy cells in the treatment area as much as possible. Side effects of radiation therapy will depend mainly on the size of the area being treated, the specific area or organs being treated, the total dose of radiation, the type of radiation you had and the treatment schedule. Tell your healthcare team if you have side effects that you think are from radiation therapy. The sooner you tell them of any problems, the sooner they can suggest ways to help you deal with them.

These are common side effects of radiation therapy for uterine cancer:

• pain or mild cramping
• fatigue
• skin problems, such as redness, itchiness and dryness at the site where radiation was given
• nausea and vomiting
• swelling and bruising in the pubic area
• bladder problems, including discomfort, urge to urinate often and bleeding
• vaginal bleeding
• bowel changes, including diarrhea and more frequent bowel movements (poop)
• bowel obstruction
• sexual problems, including vaginal dryness and painful intercourse
• fertility problems, including infertility
• low blood cell counts

Find out more about radiation therapy and side effects of radiation therapy. To make the decisions that are right for you, ask your healthcare team questions about radiation therapy.