Understanding Why Colorectal Cancer Rates are Surging in Adults Under 50

In the 1990s, colorectal cancer was the fourth-leading cause of cancer deaths in men and women under 50. But the latest data from the American Cancer Society (ACS) has found a striking shift: Colorectal cancer is now the top cause of cancer death in men under 50, and second to only breast cancer for women under 50.

March is Colorectal Cancer Awareness and this year the concerning trend among younger adults is getting much of the attention, partly because the factors behind their surging rates of diagnoses are unclear.

Overall, the rate of people being diagnosed with colorectal cancer each year has dropped overall since the mid-1980s. That’s primarily due to more people getting screened and modifying lifestyle-related risk factors, including weight management, healthier eating and regular physical activity.

From 2011 to 2019, colorectal cancer incidence rates dropped by about 1 percent each year. But this downward trend is mostly in older adults. In people younger than 55 years of age, rates have been increasing by 1 percent to 2 percent a year since the mid-1990s, states the ACS.

Sarah Joseph, M.D., medical oncologist at Baptist Health Miami Cancer Institute

More Research Needed on Genetic Factors

Clinical studies on colorectal cancer have not discerned all the genetic factors behind early-onset diagnoses, explains Sarah Joseph, M.D., medical oncologist at Baptist Health Miami Cancer Institute who specializes in gastrointestinal cancers.

“We've diagnosed certain genes that predispose patients to developing cancer,” said Dr. Joseph. “But  there are other genes that we still have yet to sequence. On that forefront, we have a lot of work to do to figure out if we are missing genes that do predispose a subset of these patients to developing cancer at an earlier age.”

Dr. Joseph recalls that one of her youngest patients was diagnosed with metastatic colon cancer at 26. “He went through a whole slew of genetic testing and he didn't have any familial conditions. He really had no pre-inherited genetic history that would predispose him to developing this. However, he was sedentary and on the heavier side. He had certain risk factors that do predispose certain patients to developing cancers such as colon cancer.”

Colorectal cancer includes cancers of the colon or the rectum. depending on where they start. Colon cancer and rectal cancer are often grouped together because they have many features in common. The three primary factors that makes a person at higher risk of developing colorectal cancer are: A strong family history of colorectal cancer or certain types of polyps; A personal history of colorectal cancer or certain types of polyps; A personal history of inflammatory bowel disease (ulcerative colitis or Crohn’s disease).

Modifiable or Treatable Risk Factors

There are several modifiable risk factors, starting with obesity. “When you have obesity as a risk factor that also entails a more sedentary lifestyle and unhealthy dietary patterns,” said Dr. Joseph. “You may have high lipids, high blood pressure, fatty liver disease – all of these controllable conditions group patients into that cohort of patients with a higher risk of colorectal cancer.”

U.S. guidelines recommend that people 45 to 75 years of age be screened for colorectal cancer to reduce their risk of dying from this disease. Those who are at above-average risk should consult a physician and be screened at an even earlier age.

Up to one-third of people diagnosed with colorectal cancer before 50 have a family history or genetic predisposition, and should begin screening before age 45 years. 

“Patients with ulcerative colitis do have an increased risk of developing colon cancer,” explains Dr. Joseph. “We actually do screen them earlier. And then based on your initial colonoscopy, your GI (gastrointestinal) doctor will tell you: ‘Hey, I need to see you back in one year, three years, or five years. It really depends on what they see. But guidelines call screening patients at an earlier age if they have  inflammatory bowel, a history of even abdominal radiation, ulcerative colitis, and Crohn's.

Vital Importance of Family History

Dr. Joseph emphasizes that all patients, particularly those younger adults possible at higher risk, should have frank discussions with family members about any history of cancer.

“Talk about it. Genetic conditions run in the family,” said Dr. Joseph. “Not only is it colon cancer, it could be breast cancer. It can be very beneficial to just  bring up the topic with family members or in the community when you're talking with friends. Cancer is one of those things that we just don't talk about as much as we should. But you need to understand if you have a family history/genetic risk factor.”

And there is the matter of not knowing, ignoring or putting off colorectal cancer screenings. Another striking trend reported by the American Cancer Society: Nearly 80 percent of adults between the ages of 45 and 50 have not been screened.

“Many of patients don't get screened,” said Dr. Joseph. “It's not even a lack of education. It's just that they don't know that now the screening guidelines have changed. So, promoting screenings is No. 1. That’s the biggest thing that saves lives. And if we catch cancer at an earlier stage, we can cure it.”