Colorectal Cancer Screening: When to See a Doctor and What to Expect
Colorectal cancer screening is recommended for most adults starting at age 45, according to the American Cancer Society. Early detection is critical, as colorectal cancer is highly treatable when identified in its earliest stages. Individuals experiencing symptoms such as rectal bleeding, persistent changes in bowel habits, or unexplained abdominal pain should consult a healthcare provider immediately to determine the underlying cause.
When to Consult a Physician
You should prioritize a medical evaluation if you notice persistent changes in your digestive health. The Centers for Disease Control and Prevention (CDC) notes that symptoms of colorectal cancer often do not appear early on, which is why routine screening is essential even for asymptomatic individuals. Warning signs that require prompt medical attention include:
- Blood in or on the stool (bright red or very dark).
- Persistent abdominal discomfort, such as cramps, gas, or pain.
- A feeling that the bowel does not empty completely.
- Unexplained weight loss or fatigue.
- A persistent change in bowel habits, such as diarrhea, constipation, or narrowing of the stool.
The Diagnostic Process
When you discuss symptoms with a physician, they will perform a comprehensive assessment. According to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), this process typically begins with a review of your medical and family history. Your doctor will screen for specific risk factors, including a personal or family history of colorectal polyps or cancer, and inflammatory bowel diseases like ulcerative colitis or Crohn’s disease.
Following the history review, a physical exam is standard. A doctor may perform a digital rectal exam to check for abnormalities. If further investigation is necessary, they may order blood tests or imaging studies. A diagnostic colonoscopy is the gold standard for identifying abnormalities. During this procedure, a gastroenterologist uses a colonoscope—a flexible, lighted tube with a camera—to inspect the entire colon. If suspicious tissue or polyps are found, the physician can remove them during the procedure for a biopsy to check for cancerous cells.
Current Screening Guidelines
Screening schedules depend on your individual risk profile. The U.S. Preventive Services Task Force (USPSTF) recommends that adults aged 45 to 75 be screened for colorectal cancer. The frequency of screening varies by the test type:
| Test Type | Frequency |
|---|---|
| Stool-based tests (e.g., FIT, gFOBT) | Every 1 to 3 years |
| Colonoscopy | Every 10 years |
| CT colonography | Every 5 years |
| Flexible sigmoidoscopy | Every 5 years |
Individuals at higher risk, such as those with a strong family history or certain genetic syndromes, may need to begin screening before age 45 and undergo testing more frequently. It is important to consult with your primary care provider to establish a personalized screening plan based on your specific health history.
Risk Factors and Prevention
Beyond genetics, lifestyle choices play a significant role in colorectal cancer risk. The National Cancer Institute identifies several modifiable risk factors, including physical inactivity, obesity, heavy alcohol consumption, and smoking. While these factors are associated with increased risk, they do not replace the necessity of medical screening. Maintaining a healthy weight and engaging in regular physical activity are recommended as part of a general strategy to support digestive health and reduce the risk of various chronic diseases.