When to Start Screening for Colon Cancer | One Healthy Boston

Men's Health

When to Start Screening for Colon Cancer

Consisting of both colon cancer and cancer of the rectum, one in 22 men will be diagnosed with colorectal cancer at some point in his lifetime. Although it’s still the third leading cause of cancer death among both men and women, that number has been steadily declining over the past few decades – and much of that can be attributed to a push for better, more regular screenings.

What Are My Screening Options?

Screenings seek to find cancers at their earliest, most treatable stages, even before a person has any apparent symptoms. For colon cancer, there are a few recommended screening options available.


The guaiac-based fecal occult blood test (gFOBT) can be done at home. It requires stool samples (typically from 3 straight bowel movements) that are then mailed to a medical lab and analyzed for the presence of blood. However, a positive result requires a colonoscopy and biopsy of any suspicious-looking areas to confirm diagnosis. While test will need to be repeated annually, if done consistently, it’s as effective a screening tool as a colonoscopy at only a fraction of the cost.


Because cancer is, essentially, a DNA mutation, this stool sample-based test looks for abnormalities in the DNA of cells naturally sloughed during the digestive process. Like the gFOBT, samples are also analyzed for the presence of blood. Unlike the gFOBT, this test is very expensive – it can cost upwards of $600 per test. If DNA changes or blood is detected, you will still need to have a follow up with a colonoscopy to clarify the diagnosis.


This is generally the most reliable method of detecting and confirming the presence of cancer. In this test, a long, skinny, flexible camera is fed into the anus through the colon. Upon retrieval, it allows doctors to inspect the lining of the colon for abnormalities or polyps. It also allows biopsy samples to be collected during the procedure for pathological confirmation. Although the most expensive screening option, this test allows for direct visualization of the colon, and, if negative, some patients wouldn’t need further screening for 10 years.

When Should I Begin Screening?

Regardless of the method you choose, the age in which you should begin screening for colon cancer and how often you need to repeat screening depends a lot on risk factors present. For a man of average risk, I recommend getting your initial colonoscopy at the age of 50. However, if you have a first-degree relative (parent or sibling) who has been diagnosed with a colorectal cancer, screenings should begin 10 years before that relative was first diagnosed. For example, if your father was diagnosed at the age of 52, you would need to begin screening at 42.

What Increases My Risk?

Colorectal cancer risk factors include:

  • Being Overweight or Obese – Particularly in men, there’s a correlation between larger waistlines and increased risk of colon or rectal cancer.
  • Sedentary Lifestyle – Exercise and physical activity has a significant impact on your overall health as well as reduce your risk for certain kinds of cancers, including colon cancer.
  • Smoking – Long-time smokers are not only more likely to develop colorectal cancers, but are also more likely to die from the condition.
  • Alcohol Use – Moderate and heavy alcohol use has been linked to an increased risk in colorectal cancers.
  • Age – Your risk for developing colon or rectal cancer increases significantly after the age of 50.
  • Personal History – If you have a history of colorectal polyps, you’re at an increased risk of developing cancer.
  • Inflammatory Bowel Disease – IBDs like Crohn’s disease or ulcerative colitis can affect the lining of the colon or rectum over time. This condition, called dysplasia, can turn cancerous.
  • Family History – While only 1 in 3 people diagnosed have a family member with colorectal cancer, your risk increases significantly if you have first-degree relatives (mother, father, sibling) or relatives under the age of 45 who have been diagnosed.
  • Ethnicity – African-Americans have the highest risk of developing and dying from colorectal cancer among all ethnicities and racial groups in the U.S.
  • Type 2 Diabetes – Although Type 2 diabetes and colorectal cancer share some risk factors like obesity and sedentary lifestyle, diabetes alone can increase your risk for developing colorectal cancers as well as affect prognosis and outcomes.

While I can’t emphasize enough how important colorectal cancer screenings are, when to begin screening and what methods are most appropriate is ultimately a decision that you and your doctor should make together.

As a family physician, I tell patients that they want the smallest number of tests to adequately screen for colon cancer.  Colonoscopy, while the gold standard in screening, is a medical procedure that involves anesthesia and carries with it a slight chance of complications. Because of this, there is no benefit to beginning screening earlier or more frequently that you need.

If you have any questions about your colon cancer risks, what screening options make the most sense for you, or when you should start screening, don’t hesitate to ask your doctor – we’re always here to help!

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