Colorectal cancer rates are rising alarmingly among young adults worldwide, according to a comprehensive new study published in the journal Lancet Oncology. Researchers from the American Cancer Society (ACS) found that colon cancer rates in adults under 50 have increased in 27 out of 50 countries analyzed, even as rates remain stable in middle-aged and elderly populations.
"The increase in early-onset colorectal cancer is a global phenomenon," said lead researcher Dr. Hyuna Sung, senior principal scientist of cancer surveillance research at the ACS. "Previous studies have shown this rise in predominately high-income Western countries, but now, it is documented in various economies and regions worldwide."
Global Trends in Early-Onset Colorectal Cancer
The study, which analyzed data through 2017 from 50 countries and territories, revealed that the most significant annual increases occurred in New Zealand, Chile, and Puerto Rico, all experiencing growth rates of approximately 4% per year. For the most recent five-year period studied, the highest incidence rates of early-onset colorectal cancer were observed in Australia, Puerto Rico, New Zealand, the United States, and the Republic of Korea (14 to 17 cases per 100,000 population), while Uganda and India reported the lowest rates (4 per 100,000).
Gender disparities were also evident in the data. Young men experienced faster increases in colorectal cancer rates than women in Chile, Puerto Rico, Argentina, Ecuador, Thailand, Sweden, Israel, and Croatia. Conversely, young women saw more rapid increases in England, Norway, Australia, Turkey, Costa Rica, and Scotland.
In the United States specifically, the American Cancer Society reports that colorectal cancer rates increased by 2.4% annually among people younger than 50 between 2012 and 2021. Death rates in people under 55 have been rising about 1% per year since the mid-2000s, even as cases and mortality have steadily decreased among those 55 and older.
Revised Screening Guidelines
In response to these concerning trends, medical authorities have updated their screening recommendations. Dr. Jennifer Davids, chief of colon and rectal surgery at Boston Medical Center, emphasized that colorectal cancer screening should now begin at age 45, five years earlier than previously advised.
"45 is the new 50, which is really important to know," Davids stated. "I fall into that age category, so I'm in the peer group that needs to catch up and make sure we're all on top of our screening."
The U.S. Centers for Disease Control and Prevention (CDC) outlines several screening options, including colonoscopy once every ten years, CT colon scans every five years, annual stool tests for blood, or stool DNA tests every three years.
"Colonoscopy is definitely still the gold standard," Davids explained. "The reason for that is it allows us to identify polyps and early cancers and remove them all in one setting. Colorectal cancer starts in the lining of the colon and rectum and then grows through the wall into the lymph nodes and then can spread systemically. So the reason why colonoscopy is so effective is we find those polyps before they grow and mutate into cancers and we can remove them."
Recognizing Symptoms in Younger Adults
Medical experts are particularly concerned about the trend of colorectal cancer affecting increasingly younger populations. "What we're seeing is a really alarming trend where a disease that used to be considered that of middle-age or older individuals now is affecting people as young as their 20s, 30s, 40s," Davids noted. "Often those patients are presenting, thinking that their symptoms are due to stress or diet, and often they're presenting at a later stage requiring more intervention and more likelihood for surgery."
Healthcare professionals urge young adults to be vigilant about potential symptoms, which include:
- Changes in bowel movement frequency or consistency
- Difficulty passing stools
- Blood in stool or toilet bowl
- Abdominal pain or bloating
- Fatigue
- Unexplained weight loss
- Nausea or changes in appetite
"By the time an individual is having one or more of those symptoms, that suggests that cancer has progressed to the point where it's impacting the passage of stool, it's causing bleeding, or potentially leading to symptoms that could indicate spread," Davids warned. "The key is early recognition of those symptoms and seeking medical attention with either your primary or a gastroenterologist or colorectal surgeon."
Risk Factors and Prevention Strategies
Family history remains one of the most significant risk factors for colorectal cancer. Davids encourages families to discuss their medical histories openly. "People don't tend to gather at Thanksgiving, Christmas, Sundays and talk about their colorectal cancer, colonoscopy results," she said. "But it's important to do that because a lot of patients I'll have when I ask, do you have any family history? They don't know. They're afraid to ask. One of the biggest risk factors for colorectal cancer is a family history of either polyps or cancer."
Dr. Sung emphasized the need for innovative prevention approaches: "The global scope of this concerning trend highlights the need for innovative tools to prevent and control cancers linked to dietary habits, physical inactivity, and excess body weight. Ongoing efforts are essential to identify the additional factors behind these trends and to develop effective prevention strategies tailored to younger generations and local resources worldwide."
Michelle Mitchell, chief executive of Cancer Research UK, acknowledged the global nature of the issue while providing perspective on the overall risk. "A cancer diagnosis at any age has a huge impact on patients and their families -- so while it's important to note that rates in younger adults are still very low compared to people over 50, we need to understand what's causing this trend in younger people," Mitchell said.
Early Detection Saves Lives
The experts unanimously stress that early detection is crucial for successful treatment outcomes. "Raising awareness of the trend and the distinct symptoms of early-onset colorectal cancer among young people and primary care providers can help reduce delays in diagnosis and decrease mortality," Dr. Sung stated.
In cases where colorectal cancer is detected early, treatment can be minimally invasive. "In some early cancers, treatment consists of a colonoscopy with removal alone," Davids explained. "We hope to get patients in early before cancer has spread to the point where a surgery is needed or even beyond that, unfortunately, where the disease could not be cured with surgery."
As researchers continue to investigate the causes behind this global trend, healthcare systems worldwide face the challenge of adapting screening programs and raising awareness among younger populations about the importance of recognizing symptoms and seeking timely medical attention.
