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Radiation therapy involves beaming x-rays at the site of the tumor to kill the
growing cancer cells. X-rays may sterilize the tissue around the tumor site – and
possibly under the arm – and keep the cancer from spreading or returning.
Radiation is always given after breast conservation surgery (lumpectomy or a
partial/segmental mastectomy). It may also be given after a full mastectomy,
especially to women with large tumors or those with evidence of tumor cells at
the edge of the tissue that is removed. Radiation is used in both early and
advanced stage cancer, as well as in cancer that recurs in the chest wall after
mastectomy. Radiation is also used to shrink an especially large tumor prior to
surgery or to slow the growth of inoperable tumors.
There are two types of radiation. The doctor may beam a concentrated booster
dose at the original tumor site or implant radioactive materials within the breast.
Some women undergoing radiation develop a skin reaction similar to a sunburn
and complain of itchy or peeling skin. However, the skin usually regains its normal
appearance as soon as treatment ends. Radiation therapy may also cause a
temporary decrease in the bloods disease-fighting white cells and increase the
risk of developing an infection.
Follow-up Treatment
In the past few years, physicians have recognized that adjuvant (additional)
treatment may improve the survival rate in early-stage breast cancer.
Since there is no way to be sure who is likely to have a recurrence, the National
Cancer Institute now strongly recommends follow-up treatment with drugs
(chemotherapy) or hormones to improve the odds of beating breast cancer.
Doctors regard this »extra treatment« as an insurance policy, hopefully ridding the
system of any hidden cancer that may remain and preventing or at least delaying
any return of the disease.
Chemotherapy
After surgery for early-stage breast cancer, most doctors now prescribe a
combination of drugs to destroy any remaining cancer cells. Some drugs may be
swallowed or injected into a muscle. Others are injected into a vein. These
anticancer »cocktails« are given in cycles, with periods of treatment alternating
with »off therapy,« or recovery, times. The total course of chemotherapy lasts 3 to
6 months, depending on the regimen.
Radiation targets a specific part of the body. Chemotherapy, on the other hand, is
a systemic treatment: The drugs reach every part of body. The strategy is to
attack any remaining cancer cells no matter where the drugs are found.
The problem with this strategy is that the drugs are very strong. They attack many
types of cells and, as a result, can produce debilitating side effects such as
nausea, vomiting, fatigue, and hair loss. Because they can damage healthy cells,
the body is less able to fight infections and other diseases.
Despite the drawbacks, chemotherapy works. Anticancer drug treatment has
been shown to increase the chance of reaching the 10-year survival mark by 34
percent in women with early-stage disease who underwent either a modified
radical or a total mastectomy.
The even better news is that some of the newer drugs cause fewer and less
severe side effects. Some women are lucky and dont have any side effects at all.
Administering certain drugs before chemotherapy can help reduce nausea and
vomiting, too. Regular laboratory tests can alert the doctor to any damaging
effects on the bodys ability to fight infection and other diseases.
Bone Marrow Transplantation
For some cancers, very high doses of drugs are more effective than standard
doses. However, such massive doses also kill the bone marrow, which produces
blood cells. To enable use of such doses, they are followed by »rescue«
maneuvers such as bone marrow transplantation (BMT) or transplantation of
blood stem cells (stem cell support).
BMT is a dangerous and taxing procedure. About 5 percent of those who
undergo it die, even in centers experienced in its use. The procedure used to be
restricted to women whose disease had spread beyond the breast area. More
recently, however, it has been performed in women with very high-risk primary
breast cancer that has spread to multiple lymph nodes but not to other organs. At
least half of women with breast cancer who undergo BMT now fall into this latter
group. However, there is little evidence that high-dose chemotherapy plus BMT
actually improves their chances of survival. Out of five studies done to date, only
one has been positive.
Because the evidence is conflicting at this point, the American Society of Clinical
Oncology has avoided making a recommendation about the use of high-dose
chemotherapy in breast cancer. (This group is the professional organization of
physicians who specialize in treating people with cancer.)
Hormonal Therapy
Because some breast cancers seem to be nourished by the female hormone
estrogen (or sometimes progesterone), doctors often prescribe therapy that
blocks or eliminates a womans natural supply of these hormones. To confirm the
value of this therapy, the tissue removed during breast biopsy is now routinely
tested for the presence of estrogen »receptors.« If the receptors are found, the
tumor is considered a suitable candidate for hormonal therapy. Women whose
cancers contain these receptors have a better overall prognosis.
Anti-estrogen therapy usually involves use of hormone blockers, though in some
relatively rare cases, the ovaries (which make the female hormones) are removed
surgically. Tamoxifen (Nolvadex), the most widely used hormone blocker, has
proved to be very effective. It works by attaching itself to the estrogen receptors
and blocking the estrogen from doing its cancer-promoting damage. The drug is
taken twice a day for up to five years.
Tamoxifen offers a number of benefits. It may suppress recurrence of cancer in
the same breast and prevent breast cancer in the other breast. In postmenopausal
women, it may also help maintain bone density and reduce the risk of heart
disease. On the other hand, it may increase risk of endometrial cancer, and can
cause bone loss among premenopausal women. Tamoxifen has also been linked
to blood clots in the major veins and the lungs.
Raloxifene (Evista), another anti-estrogen agent that is prescribed to prevent
osteoporosis, is being studied for use in treating breast cancer or suppressing its
recurrence. It appears to have a significant preventive effect, though it has not yet
been approved for this purpose. For more information on the role of both
raloxifene and tamoxifen in preventing breast cancer from ever occurring, see
chapter 37, »Your Best Insurance Against Breast Cancer.«
Megestrol acetate (Megace), another hormonal treatment, is usually used in
women with advanced breast cancers that do not respond to tamoxifen. The
doctor may also try treating advanced breast cancer with progestins or
androgens, if other hormonal therapies do not work.
Monoclonal Antibody Therapy
In September 1998, the FDA approved the first genetically engineered antibody
therapy for advanced breast cancer. The agent, called trastuzumab or Herceptin,
is used for cancers that produce too much of a certain protein (called the
HER-2/nue). When trastuzumab combines with this protein, the cell is unable to
divide and eventually dies. About 25 percent to 30 percent of patients with
metastatic breast cancer have tumor cells that express too much of this protein.
For these women, trastuzumab provides improved response to treatment when
given with other, standard forms of chemotherapy.
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