Colorectal Cancer is rising among young people

In this Article (Index)

• Colorectal cancer
• What is colorectal cancer?
• Facts and numbers about colorectal cancer
• An alarming trend among young adults
• Why is it on the rise among youg adults?
• Preventive steps

Colorectal cancer

What is colorectal cancer?

Colorectal cancer is a cancer that develops in the colon or the rectum. The colon is also known as the large intestine is the final part of the bowels, located after the small intestine, it receives the food that has been digested there and absorbs nutrients and water. The remaining waste or stool proceeds to the rectum where it is stored until it is released.

Colorectal cancer may be either colon cancer, affecting the colon, or rectal cancer, develops in the rectum. (4)

Facts and numbers about colorectal cancer

According to the American Cancer society, in the United States, there will be almost 106,600 new cases of colon cancer and around 46,200 cases of rectal cancer. It is, after skin cancers, the third most common cancer diagnosed in America, and the second deadliest; it will cause around 53,000 deaths in 2024.

The risk of developing colorectal cancer is around 1:25 for women and 1:23 for men. (1)

Globally it is the 4^th most deadly cancer, causing nearly 900,000 deaths each year. (2)

The upside is that since the 1980s, as more people are getting screened, more colorectal polyps are detected early and removed before they develop into cancer. The incidence rate is dropping roughly 1% per year among the older adults.

An alarming trend among young adults

Among Americans younger than 55 years of age, the incidence rate has been growing since the mid 1990s at 1% to 2% each year. With death rates growing 1% yearly since the mid 2000s. (1)

Colorectal cancer is also killing more young adults. According to the American Cancer Society, colorectal cancer is now the leading cause of cancer deaths in men younger than 50 and the second leading cause of cancer deaths in women of the same age group. American College of Surgeons (2024) (3)

Young adults are 58% more likely than older patients to be diagnosed with this cancer, and when the diagnosis comes, the cancer has usually spread beyond the colon or rectum; a stage known as Stage IV, metastasic or distant cancer. In older adults, on the other hand, the cancer is usually detected in a localized-stage, confined to the the colorectal region. Prognosis and treatment are more complex for Stage IV cancer. (5) This delayed diagnosis leads to a higher mortality rate among the younger patients.

"It is estimated that by 2030 roughly one in 10 colon cancers and one in four rectal cancers will be diagnosed in patients who are under the age of 50. (6).

Why is it on the rise among youg adults?

The trend noticed among American adults 55 years old or younger is replicated worldwide: colorectal cancer is now the 3^rd deadliest cancer globally. But, what is the cause of it?

Several factors have combined to lead to a rising incidence of colorectal cancer among the younger adults:

• Genetics
• Lifestyle
• Microbiome
  
  • Antibiotics
  • Inflammatory Bowel Disease
• Socio-economic factors

Genetics

Roughly 20% to 30% of colorectal cancer are caused by genetics. The genetic variants include the four Lynch syndromes and pathogenic APC, BRCA1/2, MutYH variants.
If you have a first-degree relative (parents, siblings) who have had the disease, this increases your chance of developing colorectal cancer by 2 to 4 times. The younger the age of diagnosis of your relative, the higher is your risk.

Compared to older subjects, there is a larger proportion of hereditary colorectal cancer cases among the young subjects.

Many patients at risk of hereditary cancer don't comply with the recommendation to start colonoscopy screening at an earlier age. (9)

But, 80% of the cancers have a non-genetic origin, one that can't be traced to family. This means that there are other risk factors.

Lifestyle

As with most cancers, lifestyle factors play an important role. Obesity, sedentarism and diet have all been linked to an increased risk of developing colorectal cancer.

A statistical review analyzed data from 26 studies regarding the Early-Onset Colorectal Cancer or eoCRC, and concluded that:

Alcohol and obesity have the strongest association with eoCRC. Additional risk factors for eoCRC include low physical activity, cigarette smoking, sugary drinks, processed meat, and a diet poor in fruits and vegetables. Puzzono et al. (2021) (9)

Diet, with a high intake of processed and ultra processed foods is far more frequent among the younger in comparison to the elder generation. Ultra-processed foods are unhealthy.

Obesity goes hand in hand with poor diet and lack of physical activity (see the dangers of belly fat).

Diet is also linked to the microbes in the gut, and this leads to another risk factor; an altered gut microbiome.

Microbiome

Research suggests that people suffering from colorectal cancer have an altered gut microbiome in comparison to healthy people.(6)

The Gut microbiome is influenced by many factors, including diet, age, and obesity.

Specific bacteria like Bacteroides fragilis, Escherichia coli, and Fusobacterium nucleatum have been linked to colorectal cancer. For instance, a diet that is poor in fiber and high in processed meats promotes the growth of microbes that produce hydrogen sulfide (H²S), which is a carcinogenic chemical and has been linked to an increased risk of colorectal cancer. (9)

Inflammatory Bowel Disease

Among the potential risk factors for colorectal cancer, there is a potential association with increased rates of pediatric inflammatory bowel disease or IBD. (7)

IBD-associated colorectal cancer accounts for only 1% TO 2% of all cases of colorectal cancer, it accounts for 10% to 15% of all deaths among patients suffering from IBD.
Patients with inflammatory bowel diseases (IBDs), like ulcerative colitis and Crohn’s disease are six times more likely to develop colorectal cancer than those who are not affected by IBD. (8),(12)
IBD is associated to an altered gut microbiome.

Antibiotics

Exposure to antibiotics during childhood, or even while the child was in its mother's womb, has a micobiome-altering effect. A study using data from over 18,000 subjects from the The Child Health and Development Studies (1959 and 1966) in Oakland CA, USA, found that those exposed to long-acting sulfonamides antibiotics had a fourfold increase in the risk of developing colorectal cancer as adults. (10)

Another study found that using data from 7,903 cases of colorectal cancer and a control group of over 30,000 patients found that "antibiotics may have a role in color tumor formation," affecting all age groups (old and young) but particularly in the younger group with an almost 50% risk increase for them compared to a 9% increase for those 50 years of age or older. However, they didn't find links between rectal cancer and antibiotics. (11)

Socio-economic factors

As colorectal cancer is not usually expected in young adults, the healh care providers are not on the lookout for it. Blood in stool is generally dismissed as being caused by hemorrhoids instead of triggering a colonoscopy.

Timely diagnosis is also delayed because younger adults tend to lack health insurance coverage in comparison to those aged over 55 years (22% uninsured among the younger group vs. only 7% among the older group). (5)

A delayed diagnosis leads to detection of the cancer at a more advanced stage, and this leads to worse outcomes and a higher mortality rate. (6)

In less developed countries, the situation is similar, access to decent medical facilities is limited and the people are not eductated to identify colorectal cancer signals and act accordingly.

What can people do to prevent colorectal cancer?

There are many unknown factors that will require additional research, but there are some steps that everyone can take to reduce the risk of developing colorectal cancer and also reduce the risk of dying from it. (3)

• Family history. Learn about your family history of colorectal cancer. If your parents or siblings have had it, it is time to see your health care provider.
• Remain vigilant. Don't dismiss changes in bowel habits as hemorroids. Any bleeding, persistent constipation or diarrhea should be discussed with your physician.
• Screening. Being up to date with colonoscopies or other forms of screening is critical. One in four adults are not up to date with these tests.
• Adopt a healhty lifestyle. Eat a balanced diet, with plant-based foods like legumes, whole grains, leafy vegetables. Add fiber, and probiotics, and less processed and ultraprocessed foods to your diet. If you are overweight start a weight loss program, walk, do more physical activity.