Appropriate Colon Cancer Screening for Average-Risk Female
For an average-risk female with no family history of colon cancer, the most appropriate screening option from the choices provided is B. Annual Fecal Occult Blood Testing (specifically annual FIT - Fecal Immunochemical Test), as this represents a first-tier screening option alongside colonoscopy every 10 years. 1
Why Annual FIT is the Correct Answer
The U.S. Multi-Society Task Force on Colorectal Cancer designates colonoscopy every 10 years and annual FIT as first-tier screening options for average-risk individuals starting at age 50 (or age 45 in some recent guidelines). 1 These are considered the cornerstone tests regardless of how screening is offered. 2
- Annual fecal occult blood testing (specifically FIT) is strongly recommended by multiple major guideline organizations including ACOG, AMA, ACS, and USPSTF for average-risk screening beginning at age 50. 1
- The test should be performed annually to maintain its effectiveness as a screening modality. 1, 3
Why the Other Options Are Incorrect
Colonoscopy Every 5 Years (Option A)
- Colonoscopy is recommended every 10 years, not every 5 years, for average-risk individuals with no family history. 1
- The 5-year interval is reserved for higher-risk patients, such as those with a first-degree relative diagnosed with colorectal cancer before age 60. 1, 4
- Every-5-year colonoscopy would represent over-screening in this average-risk patient and is not cost-effective. 1
Annual Sigmoidoscopy (Option C)
- Sigmoidoscopy is recommended every 5 to 10 years, not annually. 1
- ACOG recommends sigmoidoscopy every 3-5 years after age 50, while the Multi-Society Task Force recommends every 5-10 years. 1
- Annual sigmoidoscopy would be excessive, uncomfortable for patients, and not supported by any major guideline. 1
- Flexible sigmoidoscopy is now considered a second-tier test due to its inability to visualize the entire colon and declining popularity. 1
Screening Algorithm for Average-Risk Patients
First-tier options (offer these first): 1
- Colonoscopy every 10 years, OR
- Annual FIT (Fecal Immunochemical Test)
Second-tier options (if patient declines first-tier): 1
- CT colonography every 5 years
- FIT-fecal DNA every 3 years
- Flexible sigmoidoscopy every 5-10 years
Critical Caveats
- Age to begin screening: Most guidelines recommend starting at age 50 for average-risk individuals, though some newer guidelines suggest age 45. 1, 3
- Quality matters: For FIT programs, quality monitoring is essential, including tracking positivity rates and follow-up colonoscopy completion rates. 1
- FIT is preferred over guaiac-based FOBT: While the question states "fecal occult blood," modern guidelines specifically favor FIT over older guaiac-based tests due to superior sensitivity and specificity. 1, 2, 3
- Positive FIT requires colonoscopy: Any positive FIT result mandates diagnostic colonoscopy for complete evaluation. 1, 2