Colon Cancer Treatments
Treatment for colon and rectal cancers depend on the stage of the cancer
(the extent to which it has spread). The standard modes of treatment are surgery,
radiation therapy and chemotherapy.
Colon Cancer Treatments - Surgery
Surgery is the main treatment for colon cancer. If the cancer is found at a very early
stage, the doctor may take out the cancer without cutting into the abdomen. Instead the
doctor may put a tube through the rectum into the colon and cut the tumor out. This procedure is called a local
excision. If the cancer is found in a polyp, the operation is called a polypectomy. If the
cancer is larger but confined to a portion of the colon, the abdomen is opened up and the
cancerous growth and a small piece of normal tissue from either side of the cancer is
removed. This procedure is called segmental resection. If there is any likelihood of the
cancer having spread to the nearby lymph nodes, they may be removed as well. The remaining
sections of the colon are then attached back together.
If the doctor is not able to sew the colon back together, he will make an opening
called the stoma on the outside of the body for the waste material to pass out of the
body. This is called a colostomy. Sometimes the colostomy is temporary until the colon is
healed and then it can be reversed. However, if the surgery involves taking out the entire
lower colon, a permanent colostomy is needed. The patient will need to wear a special bag
to collect body wastes. This bag attaches to the body around the opening (stoma) with a
special glue and can be thrown away after it is used. The bag is hidden by the clothing.
The hospital personnel will educate the patients on how to take care of these bags
themselves.
In the case of rectal cancer, different surgical methods are used. When the cancer is
found in the polyps, a procedure known as polypectomy is used. Local excision is a
procedure that can be used to remove small superficial cancers. A small amount of
adjoining tissue is also removed from the inner layer of the rectum. If the cancer is in
the deeper layers of the rectum, local full thickness resection is used. A cut is made
through all the layers of the rectum to remove the invasive cancer as well as some
surrounding normal rectal tissue. Electrofulguration is a procedure where the cancer is
burned by passing an electric current through it. All of these methods can be done without
cutting through the abdomen.
Colon Cancer Treatments - Radiation Therapy
Radiation therapy involves the use of high-energy radiation to kill cancer cells. It
can be applied to both colon and rectal cancers. External beam radiation uses radiation
from an external source that is focused on the tumor. Internal radiation therapy uses a
small pellet of radioactive material that is implanted directly into the cancer. Radiation
therapy is generally used as adjuvant therapy, that is, it is used after the surgery to
destroy any cancerous material that may not have been removed during surgery. If the tumor
is in a place that makes surgery hard, then radiation may be used before surgery to shrink
the tumor. In advanced cancers, where surgery is not an option, radiation may be used to
ease the symptoms such as pain, blockage or bleeding.
Colon Cancer Treatments - Chemotherapy
In colorectal cancers, chemotherapy is generally used after surgery to destroy any
cancerous cells that may have migrated from the original site and spread to other parts.
The anti-cancer drugs are either given through a vein in the arm or by mouth, in the form
of pills. In the case of advanced cancers, chemotherapy may be given to alleviate symptoms
Colon Cancer Treatments - Treatment and staging.
Treatment depends partly on the "stage" of the cancer.
This means how far the tumor has spread through the layers of the intestine, from the
innermost lining to outside the intestinal wall and beyond:
- Stage 0: Very early cancer on the innermost layer (more accurately considered a
precursor to cancer)
- Stage I: Tumor in the inner layers of the colon
- Stage II: Tumor has spread through the muscle wall of the colon
- Stage III: Tumor that has spread to the lymph nodes
- Stage IV: Tumor that has spread to distant organs
Stage 0 colon cancer may be treated by cutting out the lesion, often via a colonoscopy. In some cases, more
extensive surgery may be needed (see stages I-III). For stages I, II, and III cancer,
removal of a segment of colon containing the tumor and reattachment of the colon is
necessary. This procedure only rarely requires a colostomy.
Almost all patients with stage III colon cancer, after surgery, should receive
chemotherapy (adjuvant chemotherapy) with a drug known as 5-fluorouracil given for
approximately 8 months. This drug has been shown to increase the chance of being cured.
There is some debate as to whether patients with stage II colon cancer should receive
chemotherapy after surgery, and patients should discuss this with their oncologist.
Chemotherapy is also used for patients with stage IV disease in order to shrink the
tumor, lengthen life, and improve the patient's quality of life. Irinotecan and
5-fluorouracil are the two most commonly used drugs, given either individually or in
combination. There are oral chemotherapy drugs which are similar to 5-fluroruracil, the
most commonly used being capecitabine (Xeloda).
Oxaliplatin, a newer chemotherapy drug, was approved by the FDA in 2002 and is also
active against colon cancer. It is often used in combination with 5-fluorouracil, and
studies are being done that combine it with other chemotherapy drugs. Other chemotherapy
agents, including drugs that specifically target abnormalities in cancer cells, are
currently in development and undergoing clinical trials.
For patients with stage IV disease that is localized to the liver, various treatments
directed specifically at the liver can be used. Tumors can be surgically removed, burned,
or frozen in some cases. Chemotherapy or radioactive substances can sometimes be infused
directly into the liver. |