Colorectal Cancer

Cancer of the Colon or Rectum

What is Colorectal Cancer?

Colorectal cancer (cancer of the colon or rectum) is the third most common cancer in men and women.

The average person has 1 chance in 17 of developing Colon Cancer. When discovered in its early stages, colon cancer is usually treated with surgery and often cured. Unfortunately, many people have no symptoms until the disease reaches an advanced stage and starts spreading to other organs such as the liver or lungs.

Cancer begins in cells, the building blocks that make up tissues. Tissues make up the organs of the body. Normally, cells grow and divide to form new cells as the body needs them. When cells grow old they die, and new cells take their place.

Sometimes, however, the process goes wrong. New cells form when the body does not need them, and old cells do not die when they should. These extra cells can form a mass of tissue called a tumor.

Dr. Felix Lee with Patient

Tumors are either benign or malignant. Benign tumors are rarely life-threatening and most of them can be removed. Once removed, they usually don’t grow back. Benign tumors don’t invade the tissues around them or spread to other parts of the body. On the other hand, malignant tumors are cancerous and may be life-threatening. They often can be removed, but sometimes grow back. Cancer cells can break away from a malignant tumor and spread to other parts of the body by entering the bloodstream or the lymphatic system where they can form new tumors.

When colorectal cancer spreads outside the colon or rectum, cancer cells are often found in nearby lymph nodes. If cancer cells have reached these nodes, they also may have spread to other lymph nodes or other organs. Colorectal cancer cells most often spread to the liver.

Symptoms of colorectal cancer

The most common symptom of colorectal cancer is… nothing. That’s why screening is so important. When symptoms occur, they include:

  • Diarrhea or constipation
  • Feeling that your bowel does not empty completely
  • Bright red or very dark blood in your stool
  • Narrower stools than usual
  • Frequent gas pains or cramps, or feeling full or bloated
  • Losing weight with no known reason
  • Feeling very tired all the time
  • Nausea or vomiting

Most often, these symptoms are not due to cancer. Other health problems can cause the same symptoms. Anyone with these symptoms should see a doctor to be diagnosed and treated as early as possible. Usually, early cancer does not cause pain. That’s why it’s so important not to wait to feel pain before seeing a doctor.

FAQ & Common Myths

What age do I need to start screening for colon cancer?

Typical patients need to start screening at age 50. Some patients may need to begin screening at an earlier age due to higher risk factors (inflammatory bowel disease, family history of colon cancer, etc.)

How does one develop colorectal cancer?

Colorectal cancer typically develops over time. It usually starts off as a benign growth called a colon polyp. Over a period of time, he cells in these polyps begin to grow and divide in a disorderly manner eventually leading to colorectal cancer.

Who is at risk for colorectal cancer?

Though family history or personal history of other colorectal diseases put certain individuals at higher risk of developing colorectal cancer, essentially EVERYONE has some significant risk of developing colorectal cancer. Colorectal cancer is the 2nd leading cause of cancer death and the 3rd most common form of cancer in the US with 150,000 new cases a year and over 50,000 deaths per year.

What can I do to prevent colorectal cancer?

There are certain lifestyle factors that are likely to contribute to the development of colon cancer including: SMOKING, HEAVY ALCOHOL USE, OBESITY, PHYSICAL INACTIVITY, DIETS HIGH IN RED MEATS AND LOW IN FIBER.

“I probably don’t have colon cancer since I don’t have any blood in my stool and I have no symptoms”

What makes colorectal cancer dangerous is that usually there are no symptoms. Most patients diagnosed today with colorectal cancer report having no symptoms. Usually, if there are symptoms, it can indicate a later stage of colorectal cancer.

Risk Factors for Colorectal Cancer

No one knows the exact causes of colorectal cancer. Doctors often cannot explain why one person develops this disease and another does not. Research has shown that people with certain risk factors are more likely than others to develop colorectal cancer. A risk factor is something that may increase the chance of developing a disease.

There are several such factors for colorectal cancer:

Age over 50. Colorectal cancer is more likely to occur as people get older. More than 90 percent of people with this disease are diagnosed after age 50.

Colorectal polyps. Polyps are growths on the inner wall of the colon or rectum. They are common in people over age 50. Most polyps are benign, but some polyps can become cancer. Finding and removing polyps may reduce the risk of colorectal cancer.

Family history of colorectal cancer. Close relatives (parents, brothers, sisters or children) of a person with a history of colorectal cancer are somewhat more likely to develop this disease themselves – especially if the relative had the cancer at a young age.

Genetic alterations. Changes in certain genes increase the risk of colorectal cancer. Hereditary nonpolyposis colon cancer (HNPCC) is the most common type of inherited (genetic) colorectal cancer. It accounts for about 2 percent of all colorectal cancer cases. It is caused by changes in an HNPCC gene. Most people with an altered HNPCC gene develop colon cancer, and the average age at diagnosis is 44. Familial adenomatous polyposis (FAP) is a rare, inherited condition in which hundreds of polyps form in the colon and rectum. It is caused by a change in a specific gene called APC. Unless FAP is treated, it usually leads to colorectal cancer by age 40. FAP accounts for less than 1 percent of all colorectal cancer cases.

Personal history of cancer. A person who has already had colorectal cancer may develop colorectal cancer a second time. Also, women with a history of cancer of the ovary, uterus (endometrium) or breast are at a somewhat higher risk of developing colorectal cancer.

Ulcerative colitis or Crohn’s disease. A person who has had a condition that causes inflammation of the colon (such as ulcerative colitis or Crohn’s disease) for many years is at increased risk of developing colorectal cancer.

Diet. Studies suggest that diets high in fat (especially animal fat) and low in calcium, folate and fiber may increase the risk of colorectal cancer. Also, some studies suggest that people who eat a diet very low in fruits and vegetables may have a higher risk of colorectal cancer. However, results from diet studies do not always agree, and more research is needed to better understand how diet affects the risk of colorectal cancer.

Cigarette smoking. A person who smokes cigarettes may be at increased risk of developing polyps and colorectal cancer.

How is colon cancer diagnosed?

Screening tests help find polyps or cancer before you ever experience symptoms. Finding and removing polyps may prevent colorectal cancer. Also, treatment for colorectal cancer is more likely to be effective when the disease is found early.

The following screening tests can be used to detect polyps, cancer or other abnormal areas:

Fecal occult blood test (FOBT). Sometimes cancers or polyps bleed, and the FOBT can detect tiny amounts of blood in the stool. If this test detects blood, other tests are needed to find the source of the blood. Benign conditions (such as hemorrhoids) also can cause blood in the stool. Learn more about this screening method

Sigmoidoscopy. We examine the inside of your rectum and the lower part of the colon with a lighted tube called a sigmoidoscope. If polyps are found, we remove them. The procedure to remove polyps is called a polypectomy. Learn more about this screening method

Colonoscopy. We examine the inside of your rectum and the entire colon using a long, lighted tube called a colonoscope. We remove any polyps that may be found. Colonoscopy is the most thorough of the various screening techniques. Learn more about this screening method

Double-contrast barium enema. You are given an enema with a barium solution, and air is pumped into your rectum. The  X-ray pictures allow the  radiologist to see abnormalities in the wall of the colon.  Usually, a colonoscopy is necessary to investigate any abnormal findings.

Digital rectal exam. A rectal exam is often part of a routine physical examination.

What is the treatment for colon cancer?

Many people diagnosed with colorectal cancer want to take an active part in making decisions about their medical care. It’s natural to want to learn all you can about your treatment choices. However, shock and stress after the initial diagnosis can make it hard to think of everything you might want to ask. It often helps to make a list of questions before an appointment.

The choice of treatment depends mainly on the location of the tumor in the colon or rectum and the stage of the disease. Treatment for colorectal cancer may involve surgery, chemotherapy, biological therapy or radiation therapy. Some people have a combination of treatments.

Colon cancer sometimes is treated differently from rectal cancer. Treatments for colon and rectal cancer are described separately below.

After diagnosing colorectal cancer, we will describe your treatment choices and the expected results. Working together, we will develop a treatment plan that meets your needs.

Cancer treatment is either local therapy or systemic therapy:

Local therapy. Surgery and radiation therapy are local therapies. They remove or destroy cancer in or near the colon or rectum. When colorectal cancer has spread to other parts of the body, local therapy may be used to control the disease in those specific areas.

Systemic therapy. Chemotherapy and biological therapy are systemic therapies. The drugs enter the bloodstream and destroy or control cancer throughout the body.

Because cancer treatments often damage healthy cells and tissues, side effects are common. Side effects depend mainly on the type and extent of the treatment. Side effects may not be the same for each person, and they may change from one treatment session to the next. Before treatment starts, we will explain possible side effects and suggest ways to help you manage them. Our goal is to make you comfortable by answering your questions regarding treatment and by referring you to the appropriate specialists.

Surgery is the most common treatment for colorectal cancer. There are three types:

  1. Colonoscopy: A small malignant polyp or small cancer may be removed from your colon or upper rectum with a colonoscope.
  2. Laparoscopy: Using minimally invasive techniques, select colon cancers may be removed with the aid of the laparoscope. Three or four tiny cuts are made into your abdomen. The surgeon sees inside your abdomen with the laparoscope. The tumor and lymph nodes with a margin of normal tissue are removed. The surgeon checks the rest of your abdomen to see if the cancer has spread.
  3. Open surgery: The surgeon makes an incision into your abdomen. The tumor and lymph nodes with a margin of normal tissue are removed under direct visualization. The surgeon checks the rest of your abdomen to see if the cancer has spread.

The time it takes to heal after surgery is different for each person. You may be uncomfortable for the first few days. Medicine can help control your pain. Also, it’s common to feel tired or weak for a while. Surgery sometimes causes constipation or diarrhea. Your health care team monitors you for signs of bleeding, infection or other problems requiring immediate treatment.

Colon Cancer. Most patients with colon cancer are treated with surgery. Some people have both surgery and chemotherapy. Some with advanced disease get biological therapy. A colostomy is seldom needed for people with colon cancer. Although radiation therapy is rarely used to treat colon cancer, sometimes it is used to relieve pain and other symptoms.

Rectal Cancer. For all stages of rectal cancer, surgery is the most common treatment. Some patients receive surgery, radiation therapy and chemotherapy. Some with advanced disease get biological therapy.

Usually, early cancer does not cause pain. That’s why it’s so important not to wait for symptoms to develop before seeing a doctor.

About one out of eight people with rectal cancer needs a permanent colostomy.

Radiation therapy may be used before and after surgery. Some people have radiation therapy before surgery to shrink the tumor, and some have it after surgery to kill cancer cells that may remain in the area. At some hospitals, patients may have radiation therapy during surgery. People also may have radiation therapy to relieve pain and other problems caused by the cancer.

Three types of therapy for colorectal cancer


Chemotherapy is frequently a part of treatment and we will discuss the various options with you at the appropriate time.


Some people with colorectal cancer that has spread receive a monoclonal antibody, a type of biological therapy. The monoclonal antibodies bind to colorectal cancer cells. They interfere with cancer cell growth and the spread of cancer. People receive monoclonal antibodies through a vein at the doctor’s office, hospital or clinic. Some people receive chemotherapy at the same time.


Radiation therapy may be necessary and may be part of your treatment program for some locally advanced colon cancer. Should the need arise, we will discuss this option with you.

Follow-up and support

Follow-up care after treatment for colorectal cancer is important. Even when the cancer seems to have been completely removed or destroyed, the disease sometimes returns because undetected cancer cells remained somewhere in the body after treatment. We will monitor your recovery and check for recurrence of the cancer. Checkups help ensure that any changes in health are noted and treated if needed.

Checkups may include a physical exam (including a digital rectal exam), lab tests (including fecal occult blood test and CEA test), colonoscopy, X-rays, CT scans or other tests.