Colon Cancer Rising in Young Adults

Why are rates of colon cancer increasing in younger adults?

Diagnoses of colon cancer, or colorectal cancer, are increasingly common among younger Americans. The American Cancer Society recently reported colorectal cancer rates rising by 2% annually among people younger than 50. In 2019, it adds, one in five people with colorectal cancer were age 54 and younger. 

Sang Lee, MD, chief of the USC Colorectal Surgery Program at Keck Medicine of USC, says that while it’s important for younger people to take note of their risk factors, there is no need to feel panicked. “Certainly, the rate of increase is alarming, but overall, colorectal cancer in younger age groups is still rare,” he says. 

To illustrate this point, according to data from the Centers for Disease Control and Prevention Wonder Database, the number of adults ages 30-34 diagnosed with colon cancer in 1999 was 3.8 out of every 100,000 people; in 2020, the number rose to 6.5.  

Why are younger people getting colon cancer? 

Dr. Lee, who is a clinical professor at the Keck School of Medicine of USC, says more thorough research is needed to definitively determine why colon cancer in young adults is on the rise.  

Another expert, Syma Iqbal, MD, section chief of gastrointestinal oncology with Keck Medicine and the USC Norris Comprehensive Cancer Center, adds, “It’s clear that colorectal cancer rates are rising for younger adults and have been for years. Interestingly, however, the incidence in patients over the age of 65 is declining. It’s not clear why this is the case. Up to 30% of patients diagnosed under the age of 50 have an inherited genetic syndrome or mutations — but that still leaves a majority without a clear, identifiable cause, as the increases in incidence have occurred more rapidly than can be accounted for by changes in population genetics.” 

Dr. Iqbal, who is an associate professor of clinical medicine at the Keck School of Medicine, also states, “Differences in clinical presentation and tumor phenotypes raise the question of whether early-onset colorectal cancer is a different disease, with a different mechanisms of pathogenesis, from colorectal cancer in older adults.” 

Looking at potential disease contributors, Dr. Lee says evidence suggests certain lifestyle choices are contributing to the increase — especially dietary changes. 

Eating habits have shifted dramatically over the past several decades. The American Heart Association says ultra-processed foods — which are known to be high in fat, salt and sugar — make up more than half of the products Americans eat on a regular basis today.  

“Consumption of red meat and processed foods has a significant impact,” Dr. Lee explains, adding that diets that are low in fiber are also a problem.  

Rising rates of obesity in the United States may be a factor, as excess weight is linked to an increased risk of colorectal cancer. The CDC says about 46% of men and 43% of women 40-59 years old are considered obese. 

Dr. Lee points to sedentary lifestyles as another factor. Researchers say regular physical activity may reduce the risk of colorectal cancer, but it’s estimated that most U.S. adults sit for at least six to eight hours per day — which doesn’t even include time sleeping. 

Dr. Iqbal says other contributing lifestyle factors may include alcohol consumption and smoking. 

To help reduce the risk of developing colon and rectal cancers, Dr. Lee recommends “commonsense things like maintaining a healthy weight, exercising regularly, drinking alcohol only in moderation — and don’t smoke.” 

In addition to lifestyle choices, genetics can be a factor. Families that have had multiple generations of people diagnosed with colon cancer may be at higher risk of developing the disease. Dr. Lee says patients with a first-degree relative diagnosed with colon cancer, like a parent or sibling, should consider getting screened early. Dr. Iqbal points out that “patients with a first-degree relative with colon cancer should be screened at least 10 years prior to the age their relative was when they were first diagnosed.” 

However, Dr. Lee also cautions that “the increase in colon cancer rates includes young patients without clear family history. Just because you don’t have any family history, it does not mean that you won’t get colon cancer.” 

Finally, Dr. Iqbal points out that early-onset colorectal cancer has been shown to disproportionately affect certain racial and ethnic minorities compared with non-Hispanic whites. 

What are the symptoms of colon cancer? 

Colon and rectal cancers generally do not exhibit symptoms until later, more advanced stages. That’s why Dr. Lee says it’s important for patients to take note of any changes in their bowel movements, as they could be warning signs that can be dealt with before cancer develops. 

“Younger patients may often dismiss symptoms,” Dr. Iqbal cautions. “Given the change in the pattern of this disease, however, patients with a change in bowel habits, rectal bleeding and pain should not ignore symptoms and should be assessed by their physician.” 

“Persistent constipation and rectal bleeding, especially if they don’t go away, are alarming indications that you should seek medical consultation,” Dr. Lee stresses. Other symptoms to take note of include chronic diarrhea, bloody stools, changes in stool color or consistency and abdominal pain. 

Although men and women will experience similar symptoms, Dr. Lee says it’s more common for women to overlook bleeding. “Sometimes women mistake rectal bleeding for menstrual bleeding,” he says, “so that’s something to be aware of and to seek medical treatment if it doesn’t improve.”  

What are the treatment options for colon cancer? 

“Colon cancer is one of the most curable cancers that we deal with, so I always tell patients to be hopeful,” Dr. Lee says when asked about the survival rate of colon cancer in young adults. 

When a patient is diagnosed with colon cancer, he says his team will do initial workups to determine whether both sides of the colon are affected. CT scans are used to investigate whether the cancer has spread to other areas, especially to the liver or the lungs. 

Dr. Lee says if the cancer is contained to the colon, patients can expect surgery to remove the lesions. For more advanced colon cancer, as well as rectal cancer, patients may receive chemotherapy and radiation before having surgery.  

Will updated screening guidelines help? 

In 2021, the U.S. Preventive Services Task Force lowered the recommended age to begin routine screenings from 50 to 45. Dr. Lee says he is optimistic that this could lead to reduced rates of colorectal cancers. 

“Colon cancer will usually be preceded by visible polyps, which are benign growths. If we find the polyps before they turn into cancer, and remove them completely, then we can decrease the chances that patients will develop colorectal cancer,” Dr. Lee explains. “That’s the whole purpose of screening.” 

Statistics among older adults support the idea that screening makes a big difference. Colorectal cancer rates among older adults have gradually dropped. “We can probably attribute the decline to effective screening,” Dr. Lee adds. 

“The overall rate of colorectal cancers in younger patients is still very low, but it’s important for young people to be informed of the trends,” Dr. Lee continues. “If you have some of these persistent symptoms, don’t assume it’s nothing. Get it checked out.” 

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