Radio
Therapy
Radiation therapy is treatment with
high-energy rays or particles that destroy cancer cells. This treatment
may be used to destroy cancer cells that remain in the breast, chest
wall, or underarm area after surgery. In some cases, the area treated by radiation therapy may also
include supraclavicular lymph nodes (nodes above the collarbone) and
internal mammary lymph nodes (nodes beneath the sternum ["breast bone"]
in the center of the chest). When given after surgery, radiation
therapy is usually not started until the tissues have been able to heal
for about a month. Radiation therapy is usually delayed until
chemotherapy is complete.
External beam radiation: This is the usual type of
radiation therapy for women with breast cancer. The radiation is
focused from a source outside the body on the area affected by the
cancer. This usually includes the whole breast and, depending on the
size and extent of the cancer, may include the chest wall and underarm
area as well. Radiation therapy is much like getting a diagnostic
x-ray, but the radiation is more intense. The procedure itself is
painless.
Before your treatments start, the radiation team carefully
takes measurements to determine the correct angles for aiming the
radiation beams and the proper dose of radiation. They will make some
ink marks or small tattoos on your skin that they will use later as a
guide to focus the radiation on the right area. Patients who receive
breast radiation after lumpectomy are usually treated 5 days a week in
an outpatient center for about 6 weeks, with each treatment lasting a
few minutes. A new technique to give radiation over a much shorter period
of time (5 days total) and to only the part of the breast with the
cancer is currently undergoing clinical research trials. This is called
partial breast irradiation. It is hoped that partial breast
irradiation will prove to be equal to the current standard whole breast
irradiation. However, partial breast irradiation is still experimental.
Women are encouraged to participate in the major national clinical
trial of partial breast irradiation that started in 2005 and should ask
their doctor about this.
One method being used is called Mammosite. It consists of a
balloon attached to a thin tube. The balloon is inserted into the
lumpectomy space and filled with a salt water solution. A source of
radioactivity is then temporarily placed into the balloon through the
tube. The radioactive material is inserted and removed twice daily for
5 days. The balloon is then deflated and removed.
Deodorants and antiperspirants can interfere with external
beam radiation therapy of the underarm area, so you should avoid using
them until treatments are complete. The main side effects of external beam radiation therapy are
swelling and heaviness in the breast, sunburn-like skin changes in the
treated area, and fatigue. You should avoid exposing the treated skin
to the sun because it can make the skin changes worse. These changes to
the breast tissue and skin usually go away in 6 to 12 months.
A rare complication is the development of another cancer
called angiosarcoma. In one group of 20,000 patients, 9 patients
developed this cancer about 4 to 8 years after post-lumpectomy
radiation. It is treated with mastectomy but can be fatal. For more
information see the American Cancer Society document, "Sarcoma – Adult Soft Tissue Cancer."
In some women, the breast becomes smaller and firmer after
radiation therapy. Radiation therapy of axillary lymph nodes also can
cause lymphedema. (This is discussed in the section, ""What Happens After Treatment for Breast Cancer?".) Radiation therapy is not given during pregnancy because it can harm a fetus.
Brachytherapy: Brachytherapy, also known as internal radiation,
is another way to deliver radiation therapy. Instead of aiming
radiation beams from outside the body, radioactive seeds or pellets are
placed directly into the breast tissue next to the cancer. Often this
is used to add an extra "boost" of radiation to the tumor site. This
method is also being studied in clinical trials as the only source of
radiation for women who have had lumpectomy. So far the results have
been promising, but more experience is needed with this technique
before it can be recommended as standard treatment.
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