The recent passing of actor James Van Der Beek from colorectal cancer, at the age of 46 after his diagnosis in 2023, has brought renewed attention to the increasing incidence of this disease in younger adults. While traditionally considered a disease of older individuals, colorectal cancer is now being diagnosed with greater frequency in people under 50, raising concerns among medical professionals.
The reasons behind this shift are not fully understood, though lifestyle and dietary factors are suspected to play a significant role. Numerous research groups and health institutions have expressed concern over this emerging trend.
Colorectal cancer, encompassing cancers of the colon and rectum, is the third most commonly diagnosed cancer globally and the second leading cause of cancer-related deaths. In 2020, nearly two million new cases were recorded worldwide, with approximately 190,000 occurring in individuals under the age of 50. Data indicates that while incidence rates have stabilized or even decreased in those over 50, particularly in high-income countries, rates are rising among younger adults.
This means that the increase in colorectal cancer cases isn’t being observed in the population traditionally considered most at risk – older adults. Instead, the rise is occurring in a demographic previously considered less susceptible.
The trend is particularly pronounced in the United States, where diagnoses in young adults have increased by an average of 1 to 2 percent annually since the mid-1990s. The increase has been most significant in the 20-39 age group. Individuals born in the 1990s have a four times higher risk of developing early-onset colorectal cancer compared to those born in the 1960s.
An increase in cases has also been observed in Europe over the past 25 years, with a more rapid growth rate again within the 20-39 age bracket. Variations exist across the continent, influenced by differing screening programs and healthcare management practices. Italy appears to show a slight decrease in early-onset cases since the late 1990s, though some studies suggest this decline may be stabilizing.
Globally, the increase is significant, prompting investigation into its causes. While increased diagnosis due to more effective screening programs can explain some increases in disease detection, this doesn’t appear to be the primary driver in this case. Most countries currently focus screening efforts on individuals over 50, leaving younger adults largely unscreened.
many diagnoses in younger adults occur when symptoms are already present – such as blood or mucus in the stool, or unintentional weight loss – indicating the cancer is often at a more advanced stage. The disease often begins with the formation of small growths, known as polyps, along the intestinal wall. These polyps can eventually develop into cancerous tumors and spread to other parts of the body (metastasis). Colonoscopies can identify and remove these polyps, preventing them from becoming cancerous. If the cancer is more advanced, more aggressive treatments like chemotherapy or surgical removal of part of the colon may be necessary.
Epidemiologists suggest the rise may be linked to a “cohort effect,” meaning that individuals born during the same period share similar risk factors due to shared lifestyle, environmental exposures, and dietary habits. More recent generations have different lifestyles, environmental exposures, and dietary patterns compared to previous generations, potentially increasing their risk of certain cancers, though the exact causes remain unclear.
The phenomenon is particularly evident in economically developed countries, leading to speculation about links to increased sedentary behavior, diets high in sugars and fats, and exposure to pollutants and toxins. Some research is exploring other factors, such as the impact of antibiotic use on the gut microbiome – the community of microorganisms living in our intestines that play a crucial role in digestion and nutrient absorption.
Dietary habits also contribute. In wealthier nations, there’s often a lower intake of fruits and vegetables, resulting in reduced fiber consumption, which can affect intestinal function. Alcohol and tobacco use are also factors, although their prevalence has decreased in many countries in recent years.
Clinical observations suggest that many cases of early-onset colorectal cancer affect the descending colon (on the left side) more frequently than the ascending colon. Some oncologists believe this may indicate a different disease evolution compared to cases in those over 50, with characteristics that require further investigation to determine optimal treatment strategies.
The emerging data is prompting discussion about revising screening guidelines. The American Cancer Society has already lowered the recommended age for initiating screening from 50 to 45. In Europe, the discussion is ongoing, but significant changes to guidelines haven’t yet been implemented.
