by Colon cancer rates in younger people have increased in recent years. Most worryingly, most of the cases diagnosed are at an advanced stage and researchers are not sure what causes the cancers.
According to new statistics from the American Cancer Society, the percentage of colon cancer occurring in people under the age of 55 doubled between 1995 and 2019, from 11% to 20%.
This means that, of the approximately 1.3 million people in the US living with colon cancer in the United States in 2019, approximately 273,800 were under the age of 55.
People born after 1990 — millennials and Gen Zers — are twice as likely to be diagnosed with colon cancer and four times as likely to develop rectal cancer compared to people born in 1950, according to a 2017 study published in Journal of the National Cancer Institute.
The numbers are rising at an alarming rate. A study published in 2021 in JAMA estimated that in just seven years, colon cancer will be the leading cause of cancer deaths in people aged 20-49.
“This is in stark contrast to people over the age of 50 who are eligible for screening, where rates and deaths from colon cancer have been steadily declining for many decades,” said Dr. at the Dana Farber Cancer Institute, he said in an interview.
The new statistics also showed that advanced-stage diagnoses are rapidly increasing among all colorectal cases in the US, jumping from 52% in the mid-2000s to 60% in 2019.
Most cases diagnosed in younger people are advanced cancers, Ng said. Advanced or stage 4 cancer is often cancer that cannot be cured or does not go away completely with treatment, but can sometimes be controlled.
“This type of cancer is highly asymptomatic and can remain that way for a long time,” said Dr. the tumor can grow and grow and even spread before symptoms appear to prompt someone to seek medical help.”
Many younger adults don’t yet know they might have colon cancer, which can lead them to mistake early symptoms for something else, May said.
Misdiagnoses have been found to be common among young people with colon cancer, according to previous research.
“When I was in medical training, I was taught that this is a disease of the elderly, specifically a disease of the elderly,” May said. “We know it’s now affecting people in the prime of their lives.”
Why is colon cancer increasing in younger people?
Known lifestyle risk factors, such as higher rates of obesity, younger people leading more sedentary lifestyles than they used to, and diets high in sugar and processed foods, likely contribute to the increase.
“It’s not just diet and lifestyle, there’s something else,” Ng said in an interview. “We see so many young colon cancer patients who are following very healthy lifestyles and diets.”
New data shows that the highest rates of colon cancer diagnoses are diagnosed in:
- Alaska Natives (88.5 per 100,000)
- Native Americans (46.0 per 100,000)
- Black Americans (41.7 per 100,000).
From 2010 to 2019, the incidence rate of colon cancer increased in every racial and ethnic group in the US
Genetics, including a family history of Lynch syndrome or polyps, play a role in a person’s risk of colon cancer, but only account for about 25 percent of cases in young people, according to Phillip Daschner, program director of cancer immunology, hematology. , and etiological branch of the Division of Cancer Biology of the National Cancer Institute.
“The remaining 75% of these cases fall into this category of unknown cause,” he said.
The driver is definitely a combination of environmental factors, May said.
“When something affects people who share the same birth years, then we know it’s something in the environment that has led that whole group of people to have higher rates,” he said.
The phenomenon is called the birth cohort effect.
It’s still unclear what environmental factors beyond lifestyle and diet are at play, but researchers are looking at everything from antibiotics to plastics to stress as possible culprits. It is also possible that there is an environmental toxin that has not yet been linked to colon cancer.
“The bottom line is we don’t know why this is happening,” Daschner said.
When should I get screened for colon cancer?
Colon cancer is still rare in people under the age of 50, but the recommended age a person should start has dropped in 2021 from 50 to 45.
Since the adjustment happened in the past two years, the increase in cases among people under 55 cannot be attributed to increased screening, Ng said. The fact that more cases are detected in advanced stages also precludes increased screening as diagnoses increase.
“If it was just a screening result, we would expect more local cases to be diagnosed. But unfortunately that is not what we see,” Ng said.
About 40% of newborn colon cancers are diagnosed in people aged 45-49. The reduced age of screening will be able to catch cancer in this group of people. However, cases that are increasingly being diagnosed in people in their 20s or 30s will still likely go unnoticed until symptoms appear.
“The research into what the underlying causes are and what the risk factors are is so important. We need to identify these high-risk youth and target them for earlier screening,” said Ng.
Colon cancer symptoms
The most common symptoms of colon cancer include:
- blood in the stool
- abdominal pain
- unintentional weight loss
- change in bowel habits.
- Anemia, shortness of breath and fatigue could also be warning signs.
Part of the problem for doctors and patients is that the symptoms can look like other conditions, experts say. If any of the symptoms occur and do not improve—especially if someone is experiencing more than one symptom—it should be considered a warning sign.
Research shows that if it is diagnosed early while colon cancer is still localized, the five-year survival rate is about 90%.
