Wchicken Dame Deborah James, a British journalist-turned-journalist, was diagnosed with bowel cancer when she was just 35 years old. She died less than six years later in 2022, after documenting her life with the disease and raising more than £11m ($13.7m) for bowel cancer research and awareness. Her death at such a young age shocked many. But data suggests that cases like hers are becoming more common (see table 1).
Bowel cancer, also known as colorectal cancer, is the second deadliest cancer worldwide after lung cancer. But cases in many high-income countries have fallen steadily across older age groups over the past two decades. In America, rates among people over 75 have halved, from 386 to 173 per 100,000 people; the pattern is similar for people between 65 and 74. But a specific trend appears among young people. Rates for people aged 15 to 39 almost doubled between 2000 and 2020, from three to 5.4 per 100,000. As young people are not screened, the actual number of people under 50 with bowel cancer may be much higher than the data suggests. In 2020 the pandemic also caused fewer people than usual to be diagnosed, meaning the increase could be even greater.
The reason for this trend among young people is not clear, although it corresponds to a general increase in cancer cases worldwide in people under the age of 50. Bowel cancer has previously been associated this to problems such as unhealthy lifestyle and poor diet. Studies also show that bowel cancer is linked to specific bacterial communities in the gut. One meta-analysis suggested that young people with bowel cancer have unique microbiome profiles. Because tumors take decades to grow, these factors may stretch back to childhood.
Cases can be easily missed in younger populations as the symptoms overlap with common health issues such as irritable bowel syndrome. Many doctors or patients do not consider cancer when a 30-year-old has changed in bowel habits and abdominal cramps. This means that the cancer often spreads before it is caught.
Older people are much more likely to be diagnosed with bowel cancer as screening has increased among people over 50. This has had a huge impact by catching bowel polyps before they become cancerous. . In America, rates have fallen steadily since the mid-1980s (see table 2). Similar patterns can be seen in other countries.
As a result, the universal screening age is being lowered. In America it was brought down from 50 to 45 in 2021; in Britain, it will be reduced from 60 to 50 by 2025. The US Preventive Services Task Force, an independent publicly funded panel that sets national healthcare guidelines, found that screening at 45 would prevent 24 to 28 deaths from bowel cancer. per 1,000 adults screened (across all age groups included), compared to no screening at all.
Some doctors worry that even 45 is too old. The first test usually involves a stool sample that is sent to labs that look for blood markers. The next step is a colonoscopy. Expanding this to the general population will take time and money. But a lack of understanding of why rates among young people are increasing makes it difficult to know exactly who should be tested.■
