Scientists don’t know exactly what causes colorectal cancer, but they have been able to identify some risk factors for the disease. A risk factor is anything that increases your chances of getting a disease.

Studies show that the following risk factors can increase a person’s chances of developing colorectal cancer: age, polyps, diet, personal history, family history, and ulcerative colitis.

Colorectal cancer is more likely to occur as people get older. It is more common in people over the age of 50, but younger people can get it, too. In rare cases, it can occur in adolescence.

Polyps are benign, or non-cancerous, growths on the inner wall of the colon and rectum. They are fairly common in people over age 50. Some types of polyps increase a person’s risk of developing colorectal cancer. Not all polyps become cancerous, but nearly all colon cancers start as polyps.

Diet appears to be associated with colorectal cancer risk. Among populations that consume a diet high in fat, protein, calories, alcohol, and both red and white meat, and low in calcium and folate, colorectal cancer is more likely to develop than among populations that consume a low-fat, high-fiber diet.

A diet high in saturated fat combined with a sedentary lifestyle may increase the risk of colorectal cancer. There is also evidence that smoking cigarettes may be associated with an increased risk of colorectal cancer.

Research shows that women with a history of cancer of the ovary, uterus, or breast have a somewhat increased chance of developing colorectal cancer. Also, a person who has already had colorectal cancer may develop this disease a second time.

The parents, siblings, and children of a person who has had colorectal cancer are somewhat more likely to develop this type of cancer themselves. This is especially true if the relative had the cancer at a young age. If many family members have had colorectal cancer, the chances increase even more.

Ulcerative colitis is a condition in which there is a chronic break in the lining of the colon. Having this condition increases a person’s chance of developing colorectal cancer.

Researchers have identified genetic mutations, or abnormalities, that may be linked to the development of colon cancer. They are working to unravel the exact ways these genetic changes occur.

If you have one or more of these risk factors, it doesn’t mean you will get colorectal cancer. It just increases the chances. You may wish to talk to your doctor about these risk factors. He or she may be able to suggest ways you can reduce your chances of developing colorectal cancer and plan an appropriate schedule for checkups.

Most cancers in their early, most treatable stages don’t cause any symptoms. That is why it is important to have regular tests to check for cancer even when you might not notice anything wrong.

When colorectal cancer first develops, there may be no symptoms at all. But as the cancer grows, it can cause changes that people should watch for. Common signs and symptoms of colorectal cancer include:

• a change in the frequency of bowel movements
• diarrhea, constipation, or feeling that the bowel does not empty completely

Common signs and symptoms of colorectal cancer include:

• either bright red or very dark blood in the stool
• stools that are narrower than usual
• general abdominal discomfort such as frequent gas pains, bloating, fullness, and/or cramps

Common signs and symptoms of colorectal cancer include:

• weight loss with no known reason
• constant tiredness
• vomiting

These symptoms may be caused by colorectal cancer or by other conditions. It is important to check with a doctor if you have symptoms because only a doctor can make a diagnosis. Don’t wait to feel pain. Early cancer usually doesn’t cause pain.

Lower your risk factors where possible. Colon cancer can be prevented if polyps that lead to the cancer are detected and removed. If colon cancer is found in its early stages, it is up to 90 percent curable.

Beginning at age 50, the following tools are all used for early detection. They can help identify pre-cancerous conditions. If you are younger than 50 and one of your first-degree relatives has had colon cancer, you should consult with your doctor.

Tools used for early detection:

• A fecal occult blood test, or FOBT, is a test used to check for hidden blood in the stool. Sometimes cancers or polyps can bleed, and FOBT can detect small amounts of bleeding.

Tools used for early detection:

• A sigmoidoscopy is an examination of the rectum and lower colon — or sigmoid colon — using a lighted instrument called a sigmoidoscope.

Tools used for early detection:

• A colonoscopy is an examination of the rectum and entire colon using a lighted instrument called a colonoscope.

Tools used for early detection:

• A double contrast barium enema , or DCBE, is a series of x-rays of the colon and rectum. The patient is given an enema with a solution that contains barium, a substance that outlines the colon and rectum on the x-rays.

Tools used for early detection:

• A digital rectal exam, or DRE, is an exam in which the doctor inserts a lubricated, gloved finger into the rectum to feel for abnormal areas.

If tests show that you have cancer, you should talk with your doctor and make treatment decisions as soon as possible. Studies show that early treatment leads to better outcomes.

A team of specialists often treats people with cancer. The team will keep the primary doctor informed about the patient’s progress. The team may include a medical oncologist who is a specialist in cancer treatment, a surgeon, a radiation oncologist who is a specialist in radiation therapy, and others.

Before starting treatment, you may want another doctor to review the diagnosis and treatment plan. Some insurance companies require a second opinion. Others may pay for a second opinion if you request it.

Some colorectal cancer patients take part in studies of new treatments. These studies, called clinical trials, are designed to find out whether a new treatment is safe and effective.

Often, clinical trials compare a new treatment with a standard one so that doctors can learn which is more effective. People with colorectal cancer who are interested in taking part in a clinical trial should talk with their doctor.

If the diagnosis is cancer, the doctor needs to learn the stage — or extent — of the disease. Staging is a careful attempt to find out whether the cancer has spread and, if so, to what parts of the body. More tests may be performed to help determine the stage. Knowing the stage of the disease helps the doctor plan treatment.

Here are the stages of colorectal cancer:

• Stage 0 — The cancer is very early and is found only in the innermost lining of the colon or rectum.
• Stage I — The cancer involves more of the inner wall of the colon or rectum.

Here are the stages of colorectal cancer:

• Stage II — The cancer has spread outside the colon or rectum to nearby tissue, but not to the lymph nodes. Lymph nodes are small, bean-shaped structures that are part of the body’s immune system.

Here are the stages of colorectal cancer:

• Stage III — The cancer has spread to nearby lymph nodes, but not to other parts of the body.
• Stage IV — The cancer has spread to other parts of the body. Colorectal cancer tends to spread to the liver and/or lungs.

Here are the stages of colorectal cancer:

• Recurrent — Recurrent cancer means the cancer has come back after treatment. The disease may recur in the colon or rectum or in another part of the body.

Most patients with stage 0, I, II, or III cancers can undergo treatment with the hope of a cure. Colorectal cancer rarely occurs again after 5 years, so most patients who live 5 years are considered cured. Most stage IV cancers cannot be cured, although treatment may be available to help extend life.

Treatments are available for all patients who have colon cancer. The choice of treatment depends on the size, location, and stage of the cancer and on the patient’s general health. Doctors may suggest several treatments or combinations of treatments.

The three standard treatments for colon cancer are surgery, chemotherapy, and radiation. Surgery, however, is the most common treatment for all stages of colon cancer. Surgery is an operation to remove the cancer. A doctor may remove the cancer using several types of surgery.

If the cancer is found at a very early stage, the doctor may remove it without cutting through the abdominal wall. Instead, the doctor may put a tube up the rectum into the colon and cut the cancer out. This is called a local excision. If the cancer is found in a polyp, which is a small bulging piece of tissue, the operation is called a polypectomy.

If the cancer is larger, the surgeon will remove the cancer and a small amount of healthy tissue around it. This is called a colectomy. The surgeon may then sew the healthy parts of the colon together. Usually, the surgeon will also remove lymph nodes near the colon and examine them under a microscope to see whether they contain cancer.

If the doctor is not able to sew the two ends of the colon back together, an opening called a stoma is made on the abdomen for waste to pass out of the body before it reaches the rectum. This procedure is called a colostomy.

Sometimes the colostomy is needed only until the lower colon has healed, and then it can be reversed. But if the doctor needs to remove the entire lower colon or rectum, the colostomy may be permanent.

Even if the doctor removes all of the cancer that can be seen at the time of the operation, some patients may receive chemotherapy after surgery to kill any cancer cells that are left. Chemotherapy treatment after surgery — to increase the chances of a cure — is called adjuvant therapy.

Researchers have found that patients who received adjuvant therapy usually survived longer and went for longer periods of time without a recurrence of colon cancer than patients treated with surgery alone. Patients age 70 and older benefited from adjuvant treatment as much as their younger counterparts.

In fact, adjuvant therapy is equally as effective — and no more toxic — for patients 70 and older as it is for younger patients, provided the older patients have no other serious diseases.

Adjuvant chemotherapy is standard treatment for patients whose cancer is operable and who are at high risk for a recurrence of the disease. Most cases of colon cancer occur in individuals age 65 and over. But studies have shown that older patients receive adjuvant chemotherapy less frequently than younger patients.

Chemotherapy is the use of anti-cancer drugs to kill cancer cells. Chemotherapy may be taken by mouth, or it may be put into the body by inserting a needle into a vein or muscle. Chemotherapy is called systemic treatment because the drugs enter the bloodstream, travel through the body, and can kill cancer cells throughout the body.

Radiation therapy is the use of x-rays or other types of radiation to kill cancer cells and shrink tumors. Most often, doctors use it for patients whose cancer is in the rectum.

Doctors may use radiation before surgery to shrink a tumor in the rectum and make it easier to remove. Or, they may use it after surgery to destroy any cancer cells that remain in the treated area.

The radiation may come from a machine or from an implant placed directly into or near the tumor. Radiation that comes from a machine is called external radiation. Radiation that uses an implant is known as internal radiation. Some patients have both kinds of therapy.

Treatments and Research - Latest ResearchResearchers continue to look at new ways to treat, diagnose, and prevent colorectal cancer. Many are testing other types of treatments in clinical trials.

Various drugs are under study as possible treatments for colorectal cancer. In May 2002, researchers found that a drug regimen consisting of oxaliplatin, 5-fluorouracil, and leucovorin can improve outcomes for patients with colorectal cancer.

A 2005 study found that patients who took the drug Avastin^TM with their standard chemotherapy treatment had a longer survival than those who did not take Avastin. The generic name for Avastin is bevacizumab.

Scientists are also working on new vaccines and monoclonal antibodies that may improve how patients’ immune systems respond to colorectal cancers. Monoclonal antibodies are a single type of antibody that researchers make in large amounts in a laboratory.

New surgical techniques have reduced the number of patients needing a permanent colostomy. A colostomy is an opening made in the abdomen for waste to pass out of the body before it reaches the rectum. In many cases, the surgeon can reconnect the healthy parts of the colon back together after removing the cancer. This way, the colon can function just as it did before.

Scientists are looking at the role that sigmoidoscopy and colonoscopy may play in detecting early stage disease and reducing deaths from colorectal cancer.

Two studies reported in the July 20, 2000 issue of New England Journal of Medicine showed that colonoscopy can find many pre-cancerous polyps that sigmoidoscopy misses. However, more studies are needed to find out if colonoscopy can actually reduce the number of deaths from colorectal cancer.

The National Cancer Institute’s Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial, or PLCO Trial, will provide important information about the role of sigmoidoscopy and colonoscopy in reducing deaths from colon and rectal cancers.

The PLCO trial, involving 148,000 volunteers aged 55 to 74, is comparing two groups of people over a 10-year period to see if the group that receives sigmoidoscopies has fewer deaths from colorectal cancer.

Researchers have developed a test called virtual colonoscopy. This test would let doctors view the entire colon using 3-D computer graphics from a computerized tomography scan, or CT scan. This technology could reduce the need for sigmoidoscopies and colonoscopies, which are more invasive. So far, however, virtual colonoscopy has not proven to be a better method of detection.

Preventing colorectal cancer is a concern of many researchers. Many continue to pursue leads on how certain foods may lead to colorectal cancer and how other foods may help to prevent it.

Scientists are also doing research on chemoprevention — the use of drugs to prevent cancer from developing in the first place. For example, researchers found that certain anti-inflammatory drugs helped keep intestinal tumors from forming in rats. These drugs have also been evaluated in people, but several studies noting serious side effects have caused the research to proceed at a slower pace.

Studies have shown that non-steroidal anti-inflammatory drugs can keep large-bowel polyps from forming. Bowel polyps can start out benign, or non-cancerous, but can become cancerous.

Genes involved in colorectal cancer continue to be identified and understood. Hereditary nonpolyposis colorectal cancer, or HNPCC, is one condition that causes people in a certain family to develop colorectal cancer at a young age. The discovery of four genes involved with this disease has provided crucial clues about the role of DNA repair in colorectal and other cancers.

Scientists are continuing to identify genes associated with colon cancers that run in families. Using traditional screening methods on people from families that carry these genes may be another way to identify cancers at an early stage and cut deaths from colorectal cancer. Genetic screening of people at high risk may become more common in the near future.