What is Colorectal Cancer?

Colorectal cancer occurs in the colon or rectum, which are a part of the large intestine. Caused by the growth of malignant cells in the colon or rectum, colorectal cancer is believed to form from non-cancerous growths, called polyps, on the walls of the colon or rectum. As time passes, polyps may begin to grow abnormally and become cancerous.

The American Cancer Society and the American Gastroenterological Association state the following facts:

• Colorectal cancer is the third most common cancer diagnosed in men and in women in the United States.
• Colorectal cancer is the second-leading cause of cancer-related deaths in the United States.
• 80 to 90 million Americans face a higher risk of developing colorectal cancer because of age, heredity and lifestyle factors.
• Due to increased screening, earlier detection, and treatment advances, a nationwide decline in death rates from colorectal cancer has been seen over the last 15 years.
• Today, 1 million American women and men have survived colorectal cancer.

Risk Factors

Certain lifestyle factors may contribute to the increase in risk of developing colorectal cancer such as:

• A diet that is high in red, processed, or heavily cooked meat
• Sedentary lifestyle
• Obesity (particularly of the waist area rather than the hips or thighs)
• Cigarette smoking
• Diabetes
• Personal and family history
• Digestive diseases

Common Symptoms

Colorectal cancer may arise without any symptoms. Screening tests are therefore strongly recommended (such as a colonoscopy and a test for blood in the stool) to detect the cancer at its earliest stage, when the cancer is more curable.

It is advised that a doctor should be seen immediately if one of the following warning signs occurs:

• Rectal bleeding or blood in the stool
• Recurring stomach pain or cramping
• Unexplainable changes in bowel habits, such as narrow, ribbon-like stools
• Discomfort during bowel movements or constantly feeling like you need to have a bowel movement
• Loss of appetite, mysterious weight loss

Screening and Diagnosis

Early detection is essential to successful treatment and recovery; therefore, routine screening is strongly suggested. A physical examination and medical testing are required to find the cause of symptoms. Colorectal cancer screening involves a few steps. A doctor will review personal medical history, family history and potential symptoms.

Following the review, one or more of the following medical tests will be given:

• Digital rectal examination (DRE): By inserting a gloved, lubricated finger into the rectum, doctors can feel for lumps or unusual masses in the rectum.
• Fecal occult blood test: A test kit completed in the privacy of the patient's home and returned to the doctor's office is evaluated for hidden blood in the stool.
• Sigmoidoscopy: This is an outpatient procedure using a long, flexible, lighted tube to check the rectum and lower part of the colon for polyps and cancerous tumors.
• Colonoscopy: This is an outpatient procedure using a colonoscope, which is a long, flexible, lighted tube (much longer than a sigmoidoscope), that allows the doctor to view the entire colon and rectum.
• Barium enema (lower GI series): A liquid containing barium is put into the rectum and a series of x-rays are taken of the lower gastrointestinal tract.

Stages of Colorectal Cancer

If a diagnosis is made, additional examinations may be performed to determine its magnitude. This process is called staging. Knowing how far the cancer has progressed is vital when deciding what regimen of treatment might be most appropriate for the patient.

As colorectal cancer progresses from Stage 0 to Stage IV, tumors grow through the lining of the rectum or colon and spread to lymph nodes and other organs:

• Stage 0 (carcinoma in situ): Cancer is found in the innermost lining of only the rectum or colon.
• Stage I: Cancer has spread beyond the innermost wall of the rectum or colon to the middle layers.
• Stage II: Cancer is found in the middle layers or outside of the colon or rectum, but not in the lymph nodes.
• Stage III: Cancer has invaded nearby lymph nodes but not other parts of the body.
• Stage IV: Other parts of the body, such as the lungs or liver, are affected by the cancer.

Common Treatment Options

The choice of treatment for colorectal cancer depends on the stage of the disease. Doctors will determine how large the tumor has grown, how deeply it has penetrated the layers of the colon or rectum, and whether it has spread to other organs (most commonly the liver), lymph nodes, or other parts of the body. The goal of treatment is to preserve healthy tissue while killing tumors at their original point, as well as any cancer cells that have spread throughout the body. The following are examples of several treatment options:

Surgery

The most common type of treatment for colorectal cancer is surgery. During this procedure, doctors often use a colonoscopy to remove small tumors and cancerous polyps in the colon or upper rectum. For tumors that are larger in size, surgical oncologists remove cancerous cells and some of the nearby healthy tissue through an opening in the abdomen. Adjacent lymph nodes also may be removed.

Chemotherapy

Chemotherapy treatment uses drugs to stop the growth of cancer cells, either by destroying the cells or by stopping the cells from dividing. Whether the chemotherapy is given as the primary treatment or as an adjuvant (additional) treatment to surgery depends on the type and stage of cancer. Chemotherapy drugs can be taken orally or by injection. The patient's doctor will prescribe a specific drug protocol that will suit the type and stage of his/her particular cancer. Discussing treatment protocols with the treatment team is advisable in order to be aware of any possible side effects.

Radiation

When colorectal cancer has attached to an internal organ or the lining of the abdomen and the surgeon cannot be certain that all the cancer has been removed, radiation therapy is normally used. Radiation therapy is usually performed to treat rectal cancer in order to prevent the cancer from coming back in the pelvis where the tumor started.

Radiation therapy is a non-surgical method of treatment of cancer and other diseases, using beams of high-energy waves called x-rays or gamma rays. Radiation cripples or destroys tumor cells by incapacitating their genetic material, making it impossible for these cells to continue to grow. There are two types of radiation therapy:

• External-beam radiation therapy: Specialized medical equipment is used to deliver radiation to the tumor site from outside the body.
• Internal radiation therapy (also called Brachytherapy): Also known as implant radiation, radioactive material is placed in the body near the cancer cells.

The way the radiation therapy is performed depends on the type and stage of the cancer being treated.