Young adults do not show warning signs of colon cancer

Rates of colorectal cancer are increasing rapidly among adults in their 20s, 30s and 40s, and the most common warning sign of the disease is blood in the stool, according to a new scientific study. review.

Rectal bleeding is associated with a five times higher risk of colorectal cancer, according to the new analysis, which examined 81 studies including nearly 25 million patients. adults under 50 years old. worldwide.

Abdominal pain, changes in bowel habits, and anemia are other common warning signs of the disease and should not be be ignored, said the researchers who published the paper. Thursday in JAMA Network Open.

Why it matters

Rates of colon and rectal cancer have increased among young adults, while rates have decreased among older people, who are much more likely to undergo colonoscopies to detect cancers and precancerous lesions called polyps.

But even so millennials born around 1990 are almost twice as likely to have colon cancer as people born in the 1950s, and have a four times higher risk of rectal cancer, young people without a significant family history of colon cancer are only eligible for colonoscopies at the age of 45.

Doctors can also miss warning signs. Anecdotal evidence suggests that because doctors are less likely to suspect malignancies in young people, they may attribute a symptom like rectal bleeding to a benign condition like hemorrhoids, rather than cancer, said Joshua Demb, cancer epidemiologist at the University of California, San Diego. , and one of the main authors of the article.

Between the time when young adults first go to a caregiver to complain about a symptom until they receive a diagnosis, which can take four to six hours. months on average, according to the analysis. Because diagnosis is often delayed, young adults tend to have more advanced and more difficult to treat disease.

"We need to facilitate early detection, and “One way is to identify them,” said Dr. Demb.

What we don't know

The causal factors behind The increase in colon and rectal cancers among young adults was not addressed in the new analysis, and is not well understood.

Colorectal cancer has long been associated with obesity, smoking, a sedentary lifestyle, high alcohol consumption and a diet high in red meat, processed foods and sugary drinks.

New research exploring the rapid increase in colorectal cancer among young adults examines other possible causes, including environmental exposures, changes in gut bacteria and the use of certain medications, such as antibiotics.