Colorectal cancer is on the rise

Although cancer is still more common among older adults than younger ones, there has been a growing trend of new cancer diagnoses, particularly for colorectal cancer, among people under the age of 50. Since the 1990s, rates of colorectal cancer in people under 50 have increased by around 2% a year.

According to data from CDC and the National Cancer Institute, colorectal cancer cases among people under the age of 50 have increased by almost 60% since the early 2000s, going from roughly 6.4 cases per 100,000 people to over 10 cases per 100,000. 

Notably, data from the American Cancer Society shows that roughly 75% of colorectal cancer patients under 50 are only diagnosed after the disease has spread, which makes it harder to treat. Over 90% of patients with colorectal cancer survived for five years if their cancer had not spread, but only 15% of patients survived if their cancer had already spread to other organs and tissues. 

In a new study published in JAMA, researchers found that colorectal cancer is now the leading cause of cancer mortality for adults under 50. Although overall cancer death rates in this age group have decreased by 44% by 1990, colorectal cancer death rates have increased by 1% every year since 2005. 

"It is absolutely an outlier," said Rebecca Siegel, senior scientific director of surveillance research at the American Cancer Society, who led the study.

According to Andrew Chan, chief of the clinical and translational epidemiology unit at Massachusetts General Brigham, the increases in colorectal cancer deaths among younger adults "really outpace the declines in death rates from other types of cancer."

Folasade May, an associate professor of medicine in the Vatche and Tamar Manoukian Division of Digestive Diseases at the University of California, Los Angeles, said that while the decline in overall cancer deaths is welcome news, the news of rising colorectal cancer deaths among younger adults is worrying.

"It's a good-news, bad-news story, and for a colorectal cancer doctor, it's a horror story," May said. 

According to Siegel, it's crucial that young people understand their potential risk of colorectal cancer and get regular screenings. In 2021, the U.S. Preventive Services Task Force lowered the age it recommended people begin screening colorectal cancer from 50 to 45, which helped increase screening rates from around 20% to 33%.

"Half of the people diagnosed before age 50 are aged 45 to 49, so they are screening-eligible," Siegel said.

Because people under 45 typically aren't screened for colorectal cancer, health experts say that it's important that they pay attention to potential symptoms of the disease, which can include fatigue, unexplained weight loss, diarrhea, blood in the stool, and other changes to bowel habits.

"The gold standard is colonoscopy — but there are also stool-based tests that are appropriate," said Aparna Parikh, medical director of the Center for Young Adult Colorectal Cancer at the Mass General Cancer Center. "If you are having any symptoms like weight loss, blood in stool, anemia, or change in bowel habits, you should go straight to colonoscopy."