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Health Topic

Preventing Colorectal Cancer

March Is Colon Cancer Awareness Month

Julia Bastas doesn't love getting a colonoscopy, but she knows how important it is.

"I lost a 41 year-old brother and a 43-year-old sister to colon cancer," says the Somerville resident. "Both died in their 40s, so I'm not taking any chances."

At 37, Julia is below the recommended age of 50 for colonoscopy screenings, but because of her family history, she has been advised to have a colonoscopy every 1-2 years and has been referred for genetic testing to see if she and her family members harbor a genetic mutation that puts them at a higher risk for colon cancer and perhaps other cancers as well.

"It's not my favorite thing to do," notes Julia. "But it's absolutely the best thing I can do to protect myself given my family history."

Develops Slowly Over Several Years

Colorectal cancer is a cancer that develops slowly over a period of several years generally from a pre-cancerous growth. Before the cancer develops, a visible growth of tissue is seen as a pre-cancerous polyp on the inner lining of the colon or rectum. Some polyps can change into cancer. Fortunately, most will not. Only by removing colon polyps and sending them to a pathologist can it be determined whether a polyp is actually a small cancer, a pre-cancer, or an overgrowth of normal colon tissue that is of no importance.

Colorectal Cancer

Second Most Common Cancer in Men and Women

Colorectal cancer is the second most common cancer in both men (behind prostate) and women (behind breast). The American Cancer Society estimates 106,100 people in the U.S. were diagnosed with colon cancer in 2009 and another 40,000 were diagnosed with rectal cancer. Nearly 34% of those diagnosed died from the disease.

Early Detection Can Save Your Life

But that doesn't have to be the case. Improved screening methods, increased awareness and early detection have helped the death rate for colorectal cancer drop significantly over the last few years. This decline in mortality is attributed to detecting colon cancer in its earlier stages through colon cancer screening procedures when the cancer is still curable by surgery and by removing pre-cancerous polyps some of which may have gone on to become actual invasive cancers.

"What's surprising is that in the U.S. only 50% of people do have proper screening at the proper age," says Beth Israel Deaconess Medical Center Gastroenterologist Helen Shields, MD. "I think part of the problem is that people don't understand that there's an excellent life expectancy if you find the cancer and remove it early on."

Average Risk Person: Begin Screenings at Age 50, Every 10 Years Thereafter

Because 90% of colon cancer cases occur in people age 50 years or older, experts recommend screenings begin at age 50 in the average risk person with no family or personal history of colon cancer, no pre-cancerous polyps, or inflammatory bowel disease and continue every ten years thereafter if no polyp or cancer is found.

"It is after age 50 that colon cancer increases in the population and there's no endpoint. The risk for colon cancer continues to increase with each passing year," notes Dr. Shields.

High Risk Person: Begin Screenings Before Age 50, Every 1-5 Years Thereafter

People of any age with a family history of colon cancer, a history of polyps, certain gene mutations, or inflammatory bowel disease such as ulcerative colitis or Crohn's disease are at higher risk for colon cancer and usually require screening before age 50 and screening colonoscopy at shorter intervals such as every 1-2 years, every 3 years or every 5 years depending on the specific risk factor.

Screening Methods


Colonoscopy is a procedure to directly visualize the colon with the capability of removing polyps during the procedure, if they are found. The colonoscope is a slender, flexible tube with a tiny video camera attached that looks closely at the inside of the entire colon for signs of cancer, polyps, or inflammation. View a video on colonoscopy >>


In order for the doctor to view the inner linings of the colon and rectum, the colon must be completely clean. There are several clean-out preparation methods. Each requires the patient to take clear liquids for 1-2 days prior to the procedure and drink a solution that causes increased bowel movements and multiple trips to the bathroom.

"The colonoscopy is easy," notes Bastas. "It's the prep that I don't look forward to. But it's only one uncomfortable day of my life that will hopefully allow me to live healthier for the rest of my life."

The colonoscopy takes approximately 30 minutes, during which the patient is usually sedated in order to minimize the cramping discomfort as the colonoscope moves around the colon bends. Air is used to distend the colon so that the physician can adequately visualize the lining and search for polyps or cancerous growths.

Flexible Sigmoidoscopy

For patients who do not want to be sedated, there are other possible screening methods such as flexible sigmoidoscopy, where the doctor only looks at the lower portion of the colon.

Flexible Sigmoidoscopy

Frequently, no sedation is needed for this procedure. Although flexible sigmoidoscopy only evaluates one-third of the colon, several studies have shown that colon cancer is significantly decreased in patients when all polyps found on sigmoidoscopy are removed. Patients found to have pre-cancerous polyps need to undergo a complete colonoscopy to visualize the remainder of the colon.

Fecal Occult Blood Testing (FOBT)

A third screening option is fecal occult blood testing or FOBT, where patients use special stool cards three days in a row to test the stool for blood. Blood in the stool may be a warning sign of colon cancer or polyps. The cards are sent in to the hospital or physician's office to be developed and read as positive or negative for the presence of blood.

While FOBT has shown to pick up only 24% of cancers present in the colon, patients who have a yearly FOBT have a 33% decrease in colon cancer mortality if each positive stool card for blood is followed up with a colonoscopy.

A newer type of immunochemical fecal testing is similar to FOBT but it can detect blood in the stool more readily and specifically.

"It picks up significantly more cancers and polyps," says Dr. Shields. These tests are just becoming widely available, but are more expensive at present than the standard FOBT.

Flexible sigmoidoscopy, in concert with FOBT every 3 years, is a reasonable screening option that picks up more cancers than flexible sigmoidoscopy alone.

Virtual Colonoscopy

Another screening tool is called Virtual Colonoscopy, which uses CT scans to create a three dimensional model of the colon. Radiologists then examine the model for polyps or other abnormalities. If a polyp or mass is detected on the virtual colonoscopy, a regular colonoscopy will be performed to remove the mass. The screening option has excellent potential, but is not currently paid for by Medicare, unless the colonoscope cannot navigate the entire colon due to adhesions, prior surgery or sharp bends. The virtual colonoscopy completes viewing of the remaining colon for polyps and cancers.

Lifestyle Changes May Help Lower the Risk

Making lifestyle changes may also help lower the risk of colorectal cancer. For example:

  • Studies show that regular aspirin use may lower the risk of colon polyps and cancer. However, given the increased of gastrointestinal bleeding with aspirin, a physician should make the decision after discussing the pros and cons with the patient.
  • New research finds Vitamin D reduces the risk of colon cancer.
  • Regular exercise in some studies is associated with a lower risk of colon cancer.

Factors That May Increase the Risk

Factors that may elevate the risk of colon cancer:

  • Diets high in animal fat have been shown to increase cancer risk.
  • Long-term smokers are more likely than non-smokers to develop and die from colon cancer.
  • Colorectal cancer has been linked to the heavy use of alcohol.

Best Way to Protect Against Colon Cancer is Screenings

But the best way to protect against colon cancer is to get screened.

"I'm not shy about my colonoscopy," says Julia Bastas. "I tell my friends how simple and painless it is so when they turn 50, they won't think twice about getting one."

"The bottom line is every person who is 50 or older needs to get tested with one of the screening options. Screening should start sooner if you have a family history of colon cancer or inflammatory bowel disease," urges Dr. Shields. "Screening decreases your chance of dying from a potentially curable colon cancer."

Above content provided by Beth Israel Deaconess Medical Center. For advice about your medical care, consult your doctor.

Posted March 2010