More Gen Xers and millennials are suffering from colorectal cancer.

While the rates of colon and rectal cancers are climbing steeply among young and middle-aged Americans, they continue to drop among adults 55 years old and above, according to the findings of a new study. As a result, three in 10 rectal cancer diagnoses are now made in patients younger than 55.

Colorectal Cancer Rates In Different Age Groups

Led by the American Cancer Society (ACS), the new study saw that form the mid-1980s to 2013, colon cancer rates rose 1 to 2 percent every year for those in their 20s and 30s. Rates among the middle-aged or from 40 to 54 also increased but at a slower pace, or by 0.5 to 1 percent per year.

In recent decades, rectal cancer rates climbed even faster, or at around 3 percent each year for Americans in their 20s and 30s, and 2 percent every year for those 40 to 54 years old. Three out of 10 new rectal cancer cases, as a result, are now diagnosed in patients below age 55, or double the rate in 1990.

On the other hand, rates in adults ages 55 and above have generally declined for at least four decades.

The findings, discussed in the Journal of the National Cancer Institute, are “very sobering,” said lead author and ACS researcher Rebecca Siegel in a statement.

The Matter With Cancer Screening

While they didn’t determine the reason for the significant shift, the authors suggested a reconsideration of the age that cancer screening begins. They cited that in 2013, 10,400 new colorectal cancer cases were found in people in their 40s, with an added 12,800 diagnosed in individuals in their early 50s.

"These numbers are similar to the total number of cervical cancers diagnosed, for which we recommend screening for the 95 million women ages 21 to 65 years," Siegel said.

The drop in colorectal cancer incidence in recent years has been attributed to widespread screening tests such as colonoscopies, which can find precancerous polyps that can be taken out before cancer is born. These screening tests have not been deemed practical for younger groups. While there are other less invasive tests, physicians are shooting for better methods that are easier to administer.

The risk is considered higher among African-Americans, for which screening is recommended by the American College of Gastroenterology to start by age 45.

Siegel also pinpointed a complex interplay among factors already contributing to the obesity epidemic. These include dietary changes, leading a sedentary life, excess weight, as well as low fiber intake. She clarified, however, that these cancers are not linked to the human papilloma virus (HPV), which is tied to squamous cell cancers common in HPV-related anal cancer.

Signs And Symptoms

Colorectal cancer signs are usually vague, and include common digestive issues such as diarrhea, constipation, cramping, or abdominal pain.

Chris Robert, who discovered he had colon cancer at age 29, saw weight loss and appetite loss as the first symptoms.

“I lost about 20 pounds and I wasn’t really trying to lose weight, but I just didn’t enjoy eating,” he recalled in an NYT report, and just last January he had surgery to remove parts of the colon and liver where tumors had already spread.

According to ACS estimates, more than 95,000 new colon cancer cases and nearly 40,000 new rectal cancer cases will be detected in 2017. About 50,000 are expected to die from colorectal cancer in the country this year.

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