Blog 2

Colorectal cancer screening in older adults

Colorectal Cancer Overview

Colorectal cancer (CRC) affects the colon (large intestine, predominantly the right side) or rectum and is one of the most prevalent cancers worldwide, contributing to significant morbidity and mortality. It ranks as the third most common cancer globally, accounting for approximately 10% of all cancer cases. Colon cancer is the second leading cause of cancer-related deaths, with over 1.9 million new cases and more than 930,000 deaths estimated in 2020. Projections indicate that by 2040, the incidence will rise to 3.2 million new cases and 1.6 million deaths annually, largely due to an aging population.

Risk Factors

The primary risk factor for colorectal cancer is age, with most cases occurring in individuals aged 50 and older. Other risk factors include:

  • Increasing Age : The likelihood of developing CRC increases with each decade, with more than two-thirds of cases diagnosed in those over 65.
  • Family History : A personal or family history of colorectal cancer or genetic conditions like Lynch syndrome and familial adenomatous polyposis (FAP) raises the risk.
  • Personal History : Previous colorectal cancer or certain types of polyps increase the likelihood of recurrence.
  • Lifestyle Factors : Unhealthy habits, such as a diet high in processed meats and low in fruits and vegetables, sedentary behaviour, obesity, smoking, and excessive alcohol consumption, can elevate risk.

While age and genetics are beyond our control, lifestyle changes can significantly mitigate risk. Effective evidence-based screening is crucial for early detection, which improves survival rates and quality of life.

Symptoms and Diagnosis

Colorectal cancer often presents without symptoms in its early stages, making early diagnosis challenging. Symptoms that may indicate advanced cancer include:

  • Changes in bowel habits (diarrhoea, constipation, narrowing of stools)
  • Blood in the stool (bright red or dark and tar-like)
  • Abdominal pain (cramping, persistent bloating)
  • Unexplained weight loss
  • Fatigue and low iron levels (potentially leading to anaemia)

Regular screenings are essential for early detection, especially since many diagnoses occur in individuals aged 65 and older. Early-stage colorectal cancer is confined to the bowel or local lymph nodes without distant spread, offering better treatment outcomes.

Treatment Options

Treatment depends on the cancer type, stage, and the patient's medical history. Early detection significantly enhances the likelihood of effective treatment. Diagnostic methods include physical exams, imaging (CT, MRI), colonoscopy, biopsy, and molecular testing for genetic mutations.

Screening Guidelines

Regular screening is the most effective method for early detection of colorectal cancer. Recommended screening methods include:

  • Stool-Based Tests : Non-invasive tests such as the faecal occult blood test (FOBT), faecal immunochemical test (FIT) and DNA-FIT detect hidden blood or altered DNA. These can often be performed at home.
  • Direct Visualization Tests : Colonoscopy (every 10 years), CT colonography (every 5 years), and flexible sigmoidoscopy (every 5 years) allow for direct examination of the colon.

Screening is advised to begin at age 50 and continue until age 85, with specific recommendations for individuals aged 45–49 (with average risk) and considerations for those aged 76–85 based on overall health and previous screening history.

Influencing Screening Behaviour

Factors influencing colorectal cancer screening behaviours include age, education level, income, chronic diseases, family history, healthcare access, physician recommendations, and health insurance coverage. Effective screening programs have led to a 50% reduction in CRC incidence in high-income countries.

Conclusion

Implementing prevention strategies—such as adopting a healthy lifestyle, avoiding risk factors, and participating in regular screenings—can significantly reduce the incidence and impact of colorectal cancer. Timely diagnosis, appropriate treatment, and ongoing care are vital for improving survival rates and quality of life.