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Treatment of colorectal cancer depends on the size, location, and extent of
the cancer, as well as the patient’s general health. Patients often are
treated by a team of specialists that might include the following:
Gastroenterologist, a doctor who specializes in
treating diseases of the digestive system
Medical oncologist, a doctor who specializes in
the medical treatment of cancer (chemotherapy)
Radiation oncologist, a doctor who specializes in treating
cancer using radiation therapy
Several different types of treatment are used to treat colorectal cancer.
Sometimes different treatments are combined.
What treatments are available for colorectal cancer?
The main treatments for colorectal cancer are surgery, radiation therapy, and chemotherapy. Sometimes, a patient also
might consider
biological therapy or participation in clinical trials for treatment of their colorectal cancer. If
the cancer is found in the early stages, surgery generally is curative. Advanced
colorectal cancers might be treated in a variety of ways, depending on their
location.
Surgery
Surgery is the most common treatment for colorectal cancer. It usually
involves the removal of the cancer, as well as some of the surrounding healthy
tissue. In most cases, the surgeon is able to reconnect the healthy portion of
the colon or rectum. When the surgeon cannot reconnect the healthy portions, a
temporary or permanent colostomy is necessary.
A colostomy, or surgical opening (stoma) through the
wall of the abdomen into the colon, provides a new passageway for waste material
to leave the body. After a colostomy, the patient wears a special bag to collect
body waste. Some patients need a temporary colostomy to allow the lower area of
the colon or the rectum to heal after surgery. About 15 percent of colorectal
cancer patients require a permanent colostomy.
There are different types of surgery for colorectal cancer. The type of surgery used depends on how far the cancer has developed
and how much healthy tissue must be removed, as well as the general health of
the patient. The types of surgery for colorectal cancer include the following:
- Polypectomy is a procedure during which polyps—small
growths on the inner lining of the colon—are removed during a colonoscopy, a
procedure in which a special instrument is inserted into the rectum to view the
rectum and colon.
- Local excision involves removing the cancer and some tissue
of the wall of the rectum. This procedure might be done through the anus, the
opening of the rectum, or through a small cut in
the rectum. It does not require major abdominal surgery.
- Formal resection involves the total removal of parts of the
colon and surrounding tissue.
Radiation therapy
Radiation therapy, also called radiotherapy, uses high-energy rays to attack
cancer. The intent of using radiation therapy is to damage or destroy the
genetic material of cancer cells, rendering them unable to grow and thus spread.
During treatment, radiation is aimed only at the area treated. Because it
often must go through skin and other organs to reach a tumor, the body’s
healthy cells become damaged, too. The body, however, is able to repair these
damaged cells and restore them to their proper function.
Aside from its use as a single treatment, radiation therapy has been shown to
enhance the effects of chemotherapy. It also often is used in combination with
chemotherapy to shrink a tumor before its surgical removal. For tumors that are
inoperable, radiation can be effective in reducing or alleviating the pain,
bleeding, or intestinal blockage associated with these tumors.
The radiation might be delivered by special equipment that directs the
radiation from outside the body through normal tissue to the cancer. This is
called external radiation. Radiation also might come from an implant, which is a
small container of radioactive material placed directly into or near the tumor.
This is called internal radiation. Some patients have both kinds of therapy.
Chemotherapy
Chemotherapy is the use of any one or combination of cancer-killing drugs
given either intravenously (injected in the vein) or by mouth to attack
colorectal cancer. Chemotherapy might be given in several situations. The first is
called neo-adjuvant chemotherapy. Neo-adjuvant chemotherapy might be given prior
to surgery to reduce the size of the tumor to make a complete surgical removal
possible with minimal damage to other parts of the body. This is most common in
some rectal cancers.
The second type is adjuvant chemotherapy. Adjuvant chemotherapy might be
given after successful surgery to remove a tumor in either the colon or the
rectum. In this situation, there is no visible disease left inside the body, but
the doctor might be concerned that the tumor was large or involved lymph nodes and
that there might be microscopic cells remaining. Adjuvant chemotherapy is given in
an attempt to kill any microscopic cells that could be remaining, thus improving
survival.
The third type is chemotherapy given for metastatic disease (disease
that has spread). In this case, there is disease that is visible, either to the
eye or on scan. Chemotherapy is given to cause the cancer to shrink and,
hopefully, disappear. Even if the cancer does not disappear, symptoms might be
relieved. Metastatic disease might be present at diagnosis or, in some cases,
cancer can return in a distant location months or years after initial treatment.
Biological therapy
Biological therapy, also called immunotherapy, uses the body’s own immune
system to fight cancer. The immune system finds cancer cells in the body and
works to destroy them. Biological therapies are used to repair, stimulate, or
enhance the immune system’s natural anti-cancer function. Biological therapy
might be given after surgery, either alone or in combination with chemotherapy or
radiation treatment. Most biological treatments are given by injection into a
vein (IV).
Clinical trials
Clinical trials (research studies) to evaluate new ways to treat cancer are
an appropriate option for many patients with colorectal cancer. In some studies,
all patients receive the new treatment. In others, doctors compare different
therapies by giving a promising new treatment to one group of patients and the
usual (standard) therapy to another group.
What are the side effects of colorectal cancer treatment?
The side effects of surgery vary depending on the type of surgery and the
patient’s overall health. There is no pain associated with radiation therapy,
but there might be some discomfort from lying in one position to receive the
treatment. In some cases, the skin in the area of the radiation might become pink
or red and swollen. The side effects of chemotherapy vary with each person and
the drugs being used but might include nausea and vomiting, hair loss, fatigue,
and diminished sex drive. The side effects of biological therapy or therapy
given as part of a clinical trial vary with the type of treatment used. Be sure
to tell your doctor about any side effects of your treatment. He or she might be
able to help you better deal with them.
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