The Role of Genetics

When discussing colon or rectal cancer with my patients, many attribute their diagnosis to inherited genetics. However, this assumption is often misguided.

While a substantial number of colorectal cancer cases occur in individuals without any family history, approximately one in three cases can be traced back to genetic predispositions. Those with a first-degree relative who has faced this disease, especially if diagnosed before age 50 or if multiple relatives are affected, face a heightened risk. Despite this, the exact reasons for this increased susceptibility remain unclear. Factors such as inherited genetic mutations or shared environmental influences may play a role.

Rising Incidence Among Younger Individuals

The landscape of colorectal cancer is shifting dramatically, especially among younger populations. From 1995 to 2019, the share of individuals under 55 diagnosed with colorectal cancer escalated from 11% to a concerning 20%.

In the United States, out of approximately 1.3 million people diagnosed with colorectal cancer in 2019, a striking number were under 55. These statistics reveal a sobering reality: individuals born after 1990 face double the risk of being diagnosed with colon cancer and quadruple the risk for rectal cancer compared to those born in 1950.

Projected Trends in Colorectal Cancer

Perhaps most alarming is the prediction that, within the next seven years, colorectal cancer will become the leading cause of cancer-related deaths among individuals aged 20 to 49. This unsettling trend sharply contrasts with declining rates in those over 50.

A Groundbreaking Study

In a recent investigation, Dr. Wan Yang and his team from Columbia University analyzed extensive data from the SEER database to understand the incidence of colorectal cancer among younger adults. They also examined national survey data over the years to explore the correlation between weight and cancer in individuals aged 30 to 49.

The results were troubling: there has been a notable rise in overweight and obese young adults, contributing to a nearly 30% increase in colorectal cancer cases among men and a 28% rise among women.

Implications of the Findings

This study reinforces previous findings that excess weight elevates the risk of developing colorectal cancer at a younger age.

While I often view weight issues through the lens of personal behavior, we must also consider broader policies aimed at improving public health. Increased access to nutritious foods and a greater emphasis on physical activity in educational settings could help address these concerns.

Other Modifiable Risk Factors

A risk factor is any element that raises the likelihood of developing a disease, including cancer.

Some modifiable risk factors for colorectal cancer include:

• Type 2 Diabetes: This condition shares common risk factors with colorectal cancer, such as obesity and inactivity. Research indicates that individuals with type 2 diabetes still face a heightened risk even when accounting for these factors.
• Smoking: Tobacco use is linked to increased cancer risk.
• Alcohol Consumption: Moderate to heavy drinking can elevate risk.
• Diet: A long-term diet high in red and processed meats is associated with a greater risk of colorectal cancer. Cooking meats at high temperatures can produce harmful chemicals that further increase this risk. Conversely, a balanced diet rich in fruits, vegetables, and whole grains while minimizing red and processed meats can potentially lower the risk of colon cancer.

Screening Recommendations

For those considered at average risk of developing colorectal cancer, guidelines suggest starting regular screenings at age 45.

Two primary methods exist for colorectal cancer screening: stool-based tests that search for cancer signs and visual examinations of the colon and rectum.

Actionable Screening Guidelines

If you are generally healthy and expect to live for more than ten years, it is advisable to continue regular screenings until the age of 75. Between 76 and 85, the decision to continue screening should depend on personal preference, overall health, and previous screening history. Generally, screening is no longer necessary after age 85.

Individuals are considered at average risk if they do not have any of the following:

• A personal history of colon or rectal cancer or specific types of polyps
• A family history of colorectal cancer
• Inflammatory bowel disease (like ulcerative colitis or Crohn's disease)
• A suspected or confirmed colorectal cancer syndrome, such as Lynch syndrome or familial adenomatous polyposis (FAP)
• A history of radiation treatment to the abdomen or pelvis for prior cancer

Final Thoughts

In recent changes, the recommended screening age for colon and rectal cancer has been lowered from 50 to 45 years.

Have you had the appropriate screenings? It's crucial to pay attention to any symptoms that arise. When in doubt, consult a healthcare professional.

Thank you for engaging with this important topic on the link between excess weight and early-onset colorectal cancer.