Radiation Treatment for Endometrial Cancer

In women, around 15% of all cancers are invasive pelvic cancers. Of these, the most common is endometrial cancer.This cancer affects the lining of the uterus, called the endometrium.

This is the most common gynecologic cancer in the U.S., and the forth most common cancer in women. In general, this cancer has a good prognosis, because it is usually diagnosed early. Approximately three percent of women who die from cancer have endometrial cancer.

Treatments for Endometrial Cancer

The endometrial cancer treatment a woman might receive depends on the stage of her cancer, and whether it is the first instance of cancer or a recurrence.

Generally, the first time an endometrial cancer appears it is treated with surgery to remove the uterine tumor. Additional treatments such as chemotherapy and radiation therapy are typically used as adjuvant therapy. This means they are used in conjunction with surgery.

In addition, radiation therapy and chemotherapy are used in the treatment of recurrent or metastatic cancer, and might be used as palliative treatments to relieve symptoms in cases of inoperable cancer.

In terms of radiation treatments for endometrial cancer there are two types: external beam radiation therapy, and brachytherapy.

External Beam Radiation Therapy

External beam radiation therapy is the traditional radiotherapy with which most people are likely to be familiar. In this treatment the source of radiation is a machine that produces an external beam of ionizing radiation.

This radiation is capable of killing cancer cells and shrinking tumors, because ionizing radiation damages cellular DNA and causes cancer cells to die. Healthy cells surrounding the tumor are also killed off by the radiation, but these cells recover and regrow in time.

A typical course of external beam radiation therapy includes several treatments a week for between four and six weeks.

External beam radiation therapy has a number of potential side effects. These side effects occur largely as a result of the death of healthy cells surrounding the tumor.

• Loss of appetite, fatigue

• Vaginal dryness, itching, or burning

• Itchy, tender, dry, or red skin in the area where treatment was applied. Later in the course of treatment the skin might become moist and “weepy”.

• Hair loss at the site of treatment

• Frequent urination and discomfort when urinating

• Diarrhea

• Low white cell count (signaling reduced function of the immune system)

Most women who have external-beam radiation therapy for endometrial cancer will become permanently sterile. Women who might wish to have children later on should consider having eggs harvested and frozen prior to radiation therapy.

In the long term, certain complications might also arise. Scarring can occur in the vagina, which might lead to long-term pain or discomfort, especially during vaginal intercourse. Other possible long-term effects include chronic irritation of the bladder and abnormal bowel movements.

Brachytherapy

In brachytherapy radiation treatments for endometrial cancer, the approach used to deliver radiation to the tumor is very different. Brachytherapy is generally used as treatment after hysterectomy to remove the uterus. This radiation treatment involves not an external source of radiation, but an internal one. In this treatment, radioactive “seeds”, as they are called, are inserted into the vagina.

In sealed source brachytherapy, the seeds are placed inside a small sealed cylinder, and the cylinder is inserted into the vagina. In unsealed source brachytherapy, the radioactive seeds are placed directly into the vagina. Both types involve the use of ultrasound to guide the insertion of the radioactive material into the vagina.

The primary advantage of brachytherapy is that side effects and complications are substantially reduced as compared to external beam radiation therapy. This is because the radioactive seeds emit strong doses of radiation that do not penetrate far into tissues. As a result, the radiation affects the vagina, and thus can kill any remaining cancer cells, but typically does not penetrate far enough to affect the bowels or bladder.

Even so, brachytherapy is still likely to cause certain side effects, including dryness, itching, and discomfort in the vagina, especially during sex. Systemic side effects such as reduced white blood cell count, nausea, and fatigue, do not usually occur.

References

American Cancer Society: Endometrial Cancer Radiation Therapy

Jing Wang Chiang, MD, for eMedicine: Uterine Cancer

U.S. National Institutes of Health Cancer Institute: Endometrial Cancer Topics

U.S. National Institutes of Health Cancer Institute: Radiation Therapy for Cancer: Questions and Answers