Colon Cancer (Colorectal Cancer)

Source: Adapted from Know Your Options: The Definitive Guide to Choosing The Best Medical Treatments, Reader

What is colon cancer?

Colon cancer occurs when abnormal cells grow out of control and form a mass, or tumour, in your large intestine. Doctors often refer to it as ‘colorectal cancer’ because a malignancy can arise in either the colon or the rectum. (The colon is in your abdomen. It leads to the rectum, which is just above the anus.)

Many colorectal cancers begin in a polyp that eventually forms a tumour. Left untreated, the tumour can bleed, obstruct your intestines, or break through your bowel wall. In time, cancer cells may spread to lymph nodes or to other organs, such as the liver or lungs.

When diagnosed, colon cancers are graded to indicate how aggressive they are. Tests determine whether the cancer has spread (metastasized) into lymph nodes or other tissues. Each cancer is ranked according to a four-stage scale, often expressed as I through IV, to determine therapy and prognosis. People with stage I cancer, confined to the lining of the colon, have the best outlook. More than 9 of 10 patients with early-stage tumours will be alive five years after diagnosis’a figure specialists call ‘five-year survival.’ If cancer has not reappeared during this time, they’re considered cured. Those with higher-stage tumours generally do not do as well, though most with stage II or III cancers can be effectively treated.

Who is at risk for colon cancer?

Usually slow-growing, colorectal cancers often originate in a cell with genetic mutations. Some people inherit genes that allow cells causing colon cancer to develop. More often, the abnormalities arise for unknown reasons, though diet appears to play an important role.

Treatment for colon cancer

Cancer of the colon and rectum is one of the most curable of all cancers. The choice of treatments usually depends on the stage of the disease. Patients of all ages, including the very old, can benefit. For most people, surgery to remove the tumour is the first step. Depending on the degree of spread and the location of the tumour, cancer-fighting chemotherapy drugs as well as radiation therapy may also be used to increase your chances of complete cure. Doctors who specialize in cancer care (oncologists) refer to drugs used after surgery to kill any remaining microscopic cancer cells as ‘adjuvant chemotherapy.’ Your treatment will be keyed to the stage of your cancer:

• Stage I colon or rectal cancer: Both can usually be cured by surgery alone. You probably will not need additional treatments.
• Stage II colon cancer: This may be treated with surgery alone. If your cancer has spread to the outermost colon wall, some doctors recommend chemotherapy to kill microscopic cancer cells that may remain after surgery (a regimen now under debate).
• Stage II rectal cancer: Radiation and chemotherapy is standard.
• Stage III colon cancer: Chemotherapy after surgery is standard.
• Stage III rectal cancer: Doctors prescribe chemotherapy after surgery. They often recommend radition before or after surgery.
• Stage IV colon or rectal cancer: Surgery may remove tumors in the intestine or in distant organs, such as the liver or lungs. This can produce good results if there aren’t too many metastases. Chemotherapy and/or radiation may also help shrink the tumours.

Medications for colon cancer

While chemotherapy drugs are designed to kill cancer cells, they are double-edged weapons: Because they attack healthy as well as cancerous cells, they can cause nausea and vomiting, diarrhea, hair loss, fatigue, mouth sores, and other reactions. On a positive note, because the dosages can be adjusted, and medications can minimize side effects, chemotherapy patients often miss only a couple of days of work.

For several decades now, 5-fluorouracil, or 5-FU, has been the standard chemotherapy drug for colon cancer. To counter the toxic side effects of 5-FU, doctors usually give it with other drugs. The most common is leucovorin, a form of the B vitamin folic acid. These drugs are given intravenously in various combinations and schedules, so you may need to make daily or weekly visits to your treatment center over the course of several months. Doctors also implant pumps in the abdomen that continually dispense the drug. If you have metastatic disease that has spread to distant organs, 5-FU and leucovorin are usually combined with irinotecan (Camptosar), which boosts their cancer-killing effects and prolongs survival. The more you take, the greater the likelihood of side effects, so your doctor will keep a close eye on your progress.

Different medications and medication combinations are continually tested in clinical trials. Of particular note is capecitabine (Xeloda), the first oral colon cancer drug. It appears to be as effective as 5-FU for treating metastatic disease; tests are assessing its value for adjuvant chemotherapy. Other drugs, such as oxaliplatin and raltitrexed, may prolong survival and also reduce the likelihood of side effects.

Related Procedures for Colon Cancer

Most people with colon cancer can benefit from surgical resection, the medical term for removal of their tumour. The operation, called a partial colectomy, involves cutting away a piece of the colon along with some surrounding normal tissue and nearby lymph nodes in case the cancer has spread. The colon is then reconnected. The procedure may take several hours and requires general anesthesia. Your doctor will probably do various preoperative blood tests and scans to help determine the degree of spread and prepare you for the operation. If cancer occurs in the rectum, the surgery may be more complicated: Many muscles and nerves that control sexual, bowel, and urinary functions cross through this area. Aftereffects may include poor bowel or bladder control and sexual problems, but these are often reversible.
Radiation therapy may be performed after rectal surgery to help kill tumour cells left behind and decrease the risk of recurrence. You’ll probably need regular radiation treatments, five days a week, for five or six weeks. During the treatments, doctors aim high doses of x-rays at the tumour, often from different directions. The best results are obtained when a chemotherapy drug such as 5-FU is given orally or by IV infusion during the radiation.

Increasingly, doctors use preoperative radiation to help shrink large tumours and make the operation easier. It may also eliminate the need for a colostomy. Radiation can be used to relieve pain and other symptoms when the tumour cannot be surgically removed or in cases of bowel obstruction.

Doctors may also insert a metal tube-like device called a stent, to reinforce the intestinal wall or keep the intestine open, or use a technique called laser ablation, which destroys cancerous tissue with high-energy light beams, to keep the intestine open or stop bleeding. This is especially useful for those unable to tolerate surgery.

If a tumour is obstructing the bowel or the cancer has spread through the rectal muscles or into the anus, you may need a colostomy. This procedure creates an opening from the colon through the abdominal wall and allows wastes to leave the body and collect in an outside pouch. Most colon cancer operations do not require a colostomy. When one is performed, it is often temporary and can be reversed with a second operation. In addition, many appliances and techniques are available to keep bowel movements under control and help you stay clean and odour-free.

Questions for Your Doctor

• What stage is my colorectal cancer? Where is it? How far has it spread?
• What surgery will I require?
• Will I need chemotherapy? Can I do it at home, rather than coming in to a clinic?
• Do I need radiation?
• Is there a clinical trial that would be right for me?
• Am I at risk for other cancers?
• Are my family members at risk? If they are, what should they do about it?

Living with Colon Cancer

If you have been diagnosed with Colorectal Cancer, you may be feeling overwhelmed. Here are a few quick tips to help you take control of the situation.

• Stay positive. A diagnosis of cancer is often overwhelming. Marshal your energies to gather information and resources. A close network of family and friends is vital. Support groups and counseling may improve coping skills.
• Choose a hospital and surgeon with a long track record. One study found that the more often colon cancer operations are performed in a given medical center, the less likely complications from surgery will be.
• De-stress before surgery. Music and relaxation tapes used before, sometimes during, and after surgery often help allay anxiety. Meditation, exercise, yoga, biofeedback, massage, and breathing exercises may also be useful.
• Try ginger if nausea is a problem because of chemotherapy. A cup of ginger tea or the powdered herb (100 to 200 mg) every four hours may quell symptoms. Take it with food to avoid stomach irritation. Let your doctor know if you are trying ginger or other remedies. Some vitamins, herbs, and nutritional supplements can interfere with surgery or medications.
• Get regular follow-up tests. Blood and stool should be tested on a regular schedule to help detect any recurrence of colon cancer. You’ll need a colonoscopy after surgery and every few years. This allows the doctor to remove precancerous growths called polyps and very early-stage cancers. If discovered a second time, cancer can often be completely cured with an additional round of treatment.