Your Global Health Resource

Medical Asset for Publication – 2025

Colon cancer, also referred to as colorectal cancer (CRC) when including rectal cancer, is a leading cause of cancer-related morbidity and mortality worldwide. It develops in the large intestine, typically from precancerous polyps that undergo genetic and cellular changes over time. Despite advances in detection and treatment, colon cancer remains a major health concern, particularly in certain populations and age groups.

Epidemiology and At-Risk Populations

Colon cancer predominantly affects individuals over the age of 50, but the incidence among younger adults (ages 20–49) has been rising in recent decades, particularly in high-income countries. In the United States, the median age at diagnosis is approximately 66 years.

Ethnic and racial disparities are significant. African Americans have the highest incidence and mortality rates of colon cancer among all racial groups in the U.S., due to a combination of genetic factors, socioeconomic barriers, reduced access to care, and lower screening rates. Ashkenazi Jews also have a higher genetic predisposition due to inherited mutations such as those in the MLH1 or MSH2 genes. Hispanic and Native American populations experience lower screening uptake and delayed diagnosis, leading to more advanced disease at presentation.

Symptoms and Warning Signs

Colon cancer may be asymptomatic in early stages, which underscores the importance of screening. When symptoms are present, they may include:

• Rectal Bleeding or Blood in the Stool
• Persistent Changes in Bowel Habits (Diarrhea, Constipation, or Narrowing of the Stool)
• Unexplained Weight Loss
• Abdominal Pain or Cramping
• Fatigue and Anemia (due to chronic blood loss)

Diagnosis

The gold standard for diagnosis is colonoscopy, which allows for direct visualization and biopsy of suspicious lesions. Other diagnostic tools include:

• Fecal immunochemical test (FIT) or fecal occult blood test (FOBT)
• CT colonography (virtual colonoscopy)
• Carcinoembryonic antigen (CEA) blood test as a tumor marker
• Genetic testing in younger patients or those with a family history, to identify hereditary syndromes like Lynch syndrome or familial adenomatous polyposis (FAP)

Early detection through screening can prevent colon cancer or allow for treatment at a curable stage. The U.S. Preventive Services Task Force (USPSTF) now recommends initiating screening at age 45 instead of 50 for average-risk adults.

Treatment and Prognosis

Treatment depends on cancer stage and may include:

• Surgical Resection: Curative in early-stage disease
• Chemotherapy: Typically used in stages III and IV or as adjuvant therapy
• Targeted Therapy: Includes anti-EGFR drugs (e.g., cetuximab) and VEGF inhibitors (e.g., bevacizumab) for metastatic CRC
• Immunotherapy: Particularly for mismatch repair-deficient (dMMR) or microsatellite instability-high (MSI-H) tumors, showing promising outcomes

Prognosis is highly stage-dependent. The 5-year survival rate is over 90% for localized disease, about 71% for regional spread, and drops to 13% when distant metastases are present. Early detection remains the most effective way to improve survival.

Conclusion

Colon cancer is a preventable and treatable disease when caught early. Racial disparities and the rising incidence among younger adults demand focused public health strategies, including equitable access to screening and education. With advances in personalized therapy and early detection, the outlook for patients continues to improve.