Oncologists select from a number of options when treating cancer, depending on
the type and stage of the tumor involved. The major treatments currently
available are surgery, radiation therapy, chemotherapy, hormone therapy, and
immunotherapy. Often, targeting cancerous tumors requires the artful combination
of more than one type of cancer therapy.
Surgery is the most effective and fastest treatment for
tumors that are caught early and have not metastasized. It is the only option
ensuring that the entire visible tumor is eliminated. However, there is no
guarantee that all microscopic extensions of a tumor have been removed. For this
reason, surgeons may also remove a large portion of healthy tissue that
surrounds the tumor. This may not be possible if the tumor lies near or within a
vital tissue, such as a major nerve or organ.
Often, cancer surgery requires general
anesthesia, in which the patient loses consciousness, and a
hospital stay of several days. For example, women with breast cancer may have a
lumpectomy or mastectomy, surgical removal of part (or all) of the
breast. Depending on the stage of the tumor, doctors may also remove the nearby
lymph nodes and muscle tissue. As with any major surgery, mastectomies and other
major surgical cancer treatments involve some risk, and doctors must consider
the overall health of the patient, as well as the stage of the tumor.
Some cancers can be treated surgically
with less-invasive techniques, such as laser surgery. Laser surgery uses a
powerful beam of high-energy light to vaporize certain tumors of the cervix,
larynx, and skin. Physicians perform laser surgery with an endoscope inserted
through a small incision in the skin. Laser surgery and other less-invasive
surgical procedures may require only local anesthesia, in which a patient loses
feeling in one particular area of the body but never loses
consciousness
Sometimes oncologists recommend surgery to improve a patient’s quality of life,
even if it is not likely to rid the body of cancer. Surgery of this type aims to
correct a problem that is causing discomfort or disability. For example, some
cancers may spread to the spine, pressing on the spinal cord or nearby nerves.
This pressure may cause severe pain, and in some instances, paralysis. Surgical
removal of all or part of the tumor near the spine may alleviate these symptoms.
| | B. Radiation
Therapy
Therapeutic radiology uses high-energy
particles or waves, such as X rays or gamma rays, to focus damaging radiation on
the region of a tumor, inflicting genetic damage that kills cancerous cells.
Radiation therapy damages rapidly dividing cells, mostly cancer cells but also
healthy cells that reproduce quickly. This leads to side effects such as
fatigue, skin changes, and loss of appetite. Other side effects usually are
related to the treatment of specific areas, such as hair loss following
radiation treatment to the head. Radiation therapy can also cause a decrease in
the number of white blood cells, cells that help protect the body against
infection. Most side effects are short-lived, as healthy tissues recover from
radiation much better than cancer cells because healthy cells repair damaged DNA
more efficiently. |
Many short doses of radiation therapy,
instead of fewer heavier doses, can minimize side effects. The total dose and
the number of treatments depend on the size, location, and type of cancer and
the patient’s general health. Patients usually receive radiation therapy five
days a week for five to eight weeks. Weekend rest breaks allow normal cells to
recover. Unlike surgery, radiation can destroy microscopic cancer cells that have moved
into surrounding tissues. Radiation is also a safer option for older patients or
those weakened from other diseases, who may not recover well from surgery.
Oncologists may use radiation to shrink the tumor, making surgery feasible. For
other tumors, radiation may be used following surgery. However, radiation does
not always eliminate all tumor cells, and it cannot treat widespread metastases.
Like surgery, radiation therapy may be used to relieve pain and discomfort, even
when a cure is not likely.
Chemotherapy uses powerful
anticancer drugs that travel through the bloodstream, making it potentially
useful for cancers that have spread. Oncologists use about 50 different
chemotherapeutic drugs to combat cancer, generally administering more than one
drug at a time because these drugs are more powerful when combined. Taken orally
or injected into the bloodstream, chemotherapeutic drugs interfere with cancer
cells’ ability to make new DNA or divide properly. In some cases, the drugs
cause programmed cell death. Many leukemias, lymphomas, and cancers of the
testicles are successfully treated with chemotherapy. Breast, lung,
colorectal, and prostate cancer are not currently curable with chemotherapy
alone, so chemotherapy is often used in combination with other therapies. In
fact, the most common combination of cancer treatments is surgery or radiation
therapy followed by chemotherapy.
Chemotherapy often causes severe side
effects, particularly reduced resistance to infection, internal bleeding,
diarrhea, nausea, vomiting, hair loss, and insufficient oxygen in the blood,
known as anemia. Some tumors develop resistance to many drugs after
exposure to just one drug,
Some types of cancer, such as breast and
prostate cancer, depend on sex hormones to grow. Hormone therapy prevents cancer
cells from receiving or using the hormones they need. Hormone therapy may
include surgery to remove organs in the endocrine system that make
hormones. In other cases, hormone therapy relies on drugs to stop hormone
production or change the way hormones work. Antiestrogen drugs, such as
tamoxifen and raloxifene, given to women with breast cancer block the hormone
estrogen and inhibit its ability to stimulate cell growth.
Sometimes called designer estrogens, these drugs cause only mild side effects
because treatment is limited to tissues affected by hormones. Androgen blockers
are given to men with prostate cancer to block the production of
testosterone and other male hormones that may contribute to cancer
growth.
Immunotherapy , also called biologic
therapy, uses the body’s own immune system to fight cancer cells or protect the
body from side effects. Immunotherapy relies on antibodies,
naturally occurring proteins dedicated to defending the body against invasion by
foreign substances. In one kind of immunotherapy, antibodies are used to attack
tumor cells directly, while in another approach, antibodies are used to deliver
toxic agents, such as radioactive substances or drugs, which selectively target
and harm cancer cells. Monoclonal antibodies are
laboratory-produced antibodies used to fight many diseases, including cancer.
One of the newest treatments for breast cancer is a monoclonal antibody called
Herceptin, which targets cancer cells that overproduce HER-2, the protein
implicated in about one-third of all breast cancers. |
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Other forms of immunotherapy include the
use of interferon, a naturally and synthetically produced protein
that fights disease-causing agents in the body, particularly viruses.
Interferons slow the growth of tumor cells in some patients, and they stimulate
the immune system to attack cancerous cells. Another therapy, interleukin-2, is
a naturally occurring immune system chemical that stimulates a type of immune cell that attacks cancer cells. Colony
stimulating factors help regulate the production of white blood cells, enabling
the body to better combat the disease.
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