Colon Cancer Screening
Colorectal cancer is a cancer that develops in the large intestine [colon] or rectum. The primary goal of colon cancer screening is to prevent deaths from colon cancer. Screening tests can help identify cancers at an early and potentially treatable stage. With some tests, we can also prevent the development of colorectal cancer by identifying precancerous abnormal growths called adenomatous polyps; these polyps can be removed before they become malignant. Dr. Warneke suggests that all adults should undergo colon cancer screening beginning at age 50 or earlier, depending upon the person’s risk of developing colorectal cancer. We offer several tests, each of which has advantages and disadvantages. The optimal screening test depends upon a person’s preferences and his or her risk of developing colon cancer.
Effectiveness Of Colon Cancer Screening
Most colorectal cancers develop from precancerous adenomatous polyps. A small percentage of these polyps become cancerous and spread to other areas. This progression takes at least 10 years in most people. Bay Area Houston Gastro’s colon cancer screening tests work by detecting polyps or by finding early stage cancers. Regular screening for and removal of polyps can reduce a person’s risk of developing colorectal cancer by up to 90%. Early detection of cancers that are already present in the colon increases the chances of successful treatment and decreases the chance of dying as a result of the cancer.
Colon Cancer Risk Factors
Several factors increase an individual’s risk of developing colorectal cancer. Having one or more of these factors will help us determine the age at which screening should begin, the frequency of screening, and the screening tests that are most appropriate.
Small Increases in Risk
Several characteristics increase the risk of colorectal cancer. While each individual risk factor adds some risk, risk is substantially increased if several are present together.
- Family history of colorectal cancer — Having colorectal cancer in a family member increases an individual’s risk of cancer, especially if the family member is a first degree relative (a parent, brother or sister, or child), if several family members are affected, or if the cancers have occurred at an early age (e.g., before age 55 years). People with a second-degree relative (grandparent, aunt, or uncle) or third-degree relative (great-grandparent or cousin) with colorectal cancer are considered to have an average risk of colorectal cancer.
- Prior colorectal cancer or polyps — People who have previously had colorectal cancer have an increased risk of developing a new colorectal cancer. People who have had adenomatous polyps before the age of 60 years are also at increased risk for developing colorectal cancer. Screening recommendations for these groups are discussed separately.
- Increasing age — Although the average person has a 5% lifetime risk of developing colorectal cancer, 90% of these cancers occur in people older than 50 years of age. Risk increases with age throughout life.
- Lifestyle factors — Several lifestyle factors increase the risk of colorectal cancer, including:
- A diet high in fat and red meat and low in fiber
- A sedentary lifestyle
- Cigarette smoking
Factors That Decrease Risk
Factors that may decrease risk include:
- A high calcium diet — 1000 mg of calcium daily, either through diet or by taking a calcium supplement.
Large Increases in Risk
Some conditions greatly increase the risk of colorectal cancer. These include:
- Familial adenomatous polyposis
- Hereditary nonpolyposis colon cancer
- Inflammatory bowel disease
View the full PDF to read more about increases in colon cancer risk, the screening tests we offer, and recommended screening plans.
To schedule an appointment to discuss the right screening method for you, or to set up an appointment for an exam, call us at (281) 338-2861.