The Atlanta Journal-Constitution
Colon, rectal cancers rising in young people
Study shows rate continues to drop in older adults.
Cancers of the colon and rectum have been declining in older adults in recent decades and have always been considered rare in young people. But scientists are reporting a sharp rise in colorectal cancers in adults as young as their 20s and 30s, an ominous trend.
The vast majority of colorectal cancers are still found in older people, with nearly 90 percent of all cases diagnosed in people over 50. But a new study from the American Cancer Society that analyzed cancer incidence by birth year found that colorectal cancer rates, which had dropped steadily for people born between 1890 and 1950, have been increasing for every generation born since 1950. Experts aren’t sure why.
Rectal cancers are rising particularly sharply, far faster than cancers in other parts of the large intestine or colon. The American Cancer Society estimates about 13,500 new cases of colon and rectal cancers will be diagnosed in Americans under 50 this year, with more than 95,500 cases of colon cancer and nearly 40,000 cases of rectal cancer in all age groups.
“People born in 1990, like my son, have double the risk of colon cancer and quadruple the risk of rectal cancer” compared with the risk someone born in 1950 faced at a comparable age, said Rebecca Siegel, an epidemiologist with the American Cancer Society and the lead author of the new report, published in the Journal of the National Cancer Institute on Tuesday. And though the absolute risk is still small in younger people, she said, “They carry the risk forward with them as they age.”
It is the upward trend that is worrisome: The risk of colon cancer for individuals who were born in 1990 was 5 per million people in that birth group, up from 3 per million at the same stage of life for those born in 1950. And the risk of rectal cancer for those born in 1990 was 4 per million, up from 0.9 per million for those born in 1950.
Dr. Thomas Weber, a professor of surgery at SUNY Downstate Medical Center who has served on the National Colorectal Cancer Roundtable and who was not involved in the new study, said the latest research confirms the problem is real and increasing.
“There is no mistaking these dramatic increases, especially for rectal cancers,” he said, noting that the number of new colorectal cancers among people under 50 each year exceeds the total number of new cases of less common cancers like Hodgkin lymphoma.
Young people with colorectal cancer run the added risk of getting a diagnosis later in the course of their disease, when the cancer may be less treatable, because doctors typically don’t consider the diagnosis at such a young age. Kirsten Freiborg, who is now 27, complained to doctors repeatedly about having blood in her stool when she was in college, but was told she had internal hemorrhoids. She was finally given a diagnosis of advanced colon cancer a month before her graduation, when she was 22.
Freiborg’s mother, a registered nurse, “kept pushing” for more testing, Freiborg said, and eventually convinced physicians to send her for a procedure called a flexible sigmoidoscopy, which detected a large tumor in Freiborg’s colon.
“I still remember getting the phone call from the doctor who did the procedure, who was completely shocked, and said ‘I would never have guessed that a 22-year-old would have had cancer,’” said Freiborg, who was treated with surgery and chemotherapy and is now cancer-free.
Most colorectal cancers are considered a disease of aging, so any increase of its incidence in young adults, especially when rates of the disease are on the wane in older people, is both baffling and worrisome, experts say.
Colorectal cancer rates have declined overall in recent years thanks to widespread use of screening tests like colonoscopies, which can detect precancerous polyps that can be removed before cancer develops.
These screening tests have not been considered practical for a younger population, and while other, less invasive screening tests exist, doctors are hoping improved methods that will be easier to administer will be developed.
Experts also attribute lowering cancer rates to changes in risk factors, particularly lifestyle changes like smoking cessation and healthier diets. Diets that include more fruits, vegetables and fiber and less red and processed meat are linked to lower colorectal cancer risk.
Obesity and sedentary lifestyles are also associated with colorectal cancer, as are heavy alcohol use and chronic conditions like inflammatory bowel disease and Type 2 diabetes, all of which are on the rise. But experts are not entirely convinced these are the only reasons colorectal cancer is increasing among young people.
While rates of cancers tied to human papillomavirus, or HPV, have been rising in recent years, that virus causes mainly cancers of the cervix, anus or the back of the throat, and only a small number of cases of rectal cancer.
“The honest truth is nobody knows 100 percent why there is an increase,” said Dr. Mohamed E. Salem, an assistant professor at Lombardi Comprehensive Cancer Center at Georgetown University. He said that he is older than about 60 percent of his patients — and he is 42.
“It’s hard to blame it on obesity alone,” he said. “We suspect there is also something else going on.”
Dr. Jason A. Zell, an associate professor of oncology at the University of California, Irvine, who did a study in 2014 that found increasing rates of colorectal cancer among adults ages 20 to 39 in California, said the big challenge is how to shape health policy.
“By now we know the rates are going up, it’s been reported several times,” Zell said. “Now the question is, what do we do?”
The latest analysis is the largest and most detailed to date, looking at large cancer registries reporting on nearly half a million cases dating back to 1974 to assess rates by five-year age groups and birth cohorts.
It found that in adults ages 20 to 39, colon cancer rates have increased by 1 percent to 2.4 percent a year since the mid-1980s, while rates declined overall among those 55 and older.
Rates among adults 40 to 54 increased by 0.5 percent to 1.3 percent a year since the mid-1990s.
Rectal cancer incidence rates among adults in their 20s increased even more sharply, rising by 3.2 percent a year from 1974 to 2013. And while rectal cancer rates have declined overall among people 55 and older since 1974, rates in people 50 to 54 increased between 198990 and 2012-13.
By 2012-13, nearly 30 percent of all rectal cancers were being diagnosed in people under age 55, compared with 15 percent of all rectal cancers being found in this age group in 1989-90, the study reported.