A new report, recently published by The American Cancer Society, shows that the rate of colorectal cancer is increasing in young people, but is decreasing in the elderly. Why is colorectal cancer affecting more and more young people?
The report predicts that this year, among people under 50, there will be 49 new cases and 10 deaths per day. In the 1980s, the median age of diagnosis was 72. According to the most recent statistics, available from 2016, the average age is 66. Today, half of all diagnoses are among people aged 66 and under.
Colorectal cancer is the third most common cancer in the United States and the third leading cause of cancer death in both sexes. In the early 2000s, there was a reduction in the number of patients over the age of 65. It is believed to be the result of better detection methods. Between 2011 and 2016, the rate fell by 3.3% each year. But over the same period, the rate increased by 1% per year among those aged 50 to 64.
However, among people under 50, the growth of the disease is more dramatic and has been increasing since the mid-1990s, with an increase of 2.2% each year between 2011 and 2016.
“While the overall incidence and mortality rate for colorectal cancer continues to decline, this progress is increasingly limited to older adults and is overshadowed by large disparities,” said Rebecca Siegel, MPH, lead author of the report. “Unfortunately, the tools that are good at reducing the incidence of this disease are not being fully used. Among people aged 50 and over, one in three people is not up to date on the tests. Many of them have never been screened. »
Risk factors for colorectal cancer are smoking and being overweight. Unequal access to quality care, such as screening, also plays an important role in determining whether people are diagnosed at an early stage and their chances of surviving the disease. But what would be the cause of this increase in cases among the youngest?
“It’s a question everyone’s trying to answer, and it’s largely a mystery right now,” said Kimmie Ng, Md., an oncologist at the Dana-Farber Cancer Institute and director of the Young-Onset Colorectal Cancer Center at Dana-Farber/Brigham and the Women’s Cancer Care Center. “These latest cancer statistics truly reinforce previous trends and confirm that there is a real increase in colorectal cancers in young people.”
His research at the Young-Onset Colorectal Cancer Center in Danafarber collects clinical data and treatments for young people with colorectal cancer. The research also learns about the diet and lifestyle of these young people. “We’re also going to collect samples and put the pieces back together to try to find out the cause of these cancers.”
The research at the centre is part of a major $25 million investment by Cancer Research UK. The Grand Challenge project aims to investigate the role of the microbiota in the development of the disease and the treatment of colorectal cancers.
“We are analyzing hypotheses, such as the role of obesity and diet, but also the study of the microbiota. The microbiota is examined in many different diseases, but this is particularly important for colorectal cancer,” according to Kimmie Ng.
The Grand Challenge research team, which includes scientists from around the world, recently published research showing a particular strain of E. coli found in the microbiota. This could be a factor in the development of cancer.
“We will collect stool samples from our patients and examine factors such as E. Coli. We will also see if there is a difference between young people and the elderly with colorectal cancer. »
The American Cancer Society recommends that the test for colorectal cancer be done from the age of 45. But it goes against the U.S. Preventive Services Task Force, which recommends taking the test at age 50. “Right now, I see that the vast majority of insurance companies cover screening at age 50 because most of them are government-related,” says Kimmie Ng.
In any case, people under the age of 45 are not regularly screened. They must have a known genetic predisposition or family history indicating that they are at higher risk of developing the disease.
“Young people are much more likely to be diagnosed at an advanced stage than older patients. There are delays in diagnoses due to a lack of awareness. For example, young people may not be as concerned about the presence of blood in their stools or other symptoms when they are otherwise healthy,” says Kimmie Ng. She adds that increased awareness among patients and physicians and more research on risk factors is needed to increase early detection in young people.
Some of the possible symptoms of colorectal cancer are the presence of blood in the stool, changes in bowel habits, inexplicable weight loss and abdominal pain. But many of these symptoms can be linked to less serious diseases, which often delays the search for medical intervention.
“All of these symptoms are relatively unspecific and, for a young person, in most cases they are caused by less offensive diseases. But if these symptoms persist and worsen, talk to health professionals,” said Kimmie Ng.
Colorectal cancer is also stigmatized because of the nature of the symptoms. “Patients may feel very uncomfortable talking about their symptoms, or even say they have colorectal cancer, to raise awareness. This mentality does not help the cause. We need to normalize conversations about this,” said Kimmie Ng.