Sharp rise in colorectal cancers in US millennials recorded
American Cancer Society: 13,500 cases will be diagnosed in Americans under 50 in 2017
Young people with colorectal cancers run the risk of getting a diagnosis later in the course of their disease because doctors typically do not consider the diagnosis at such a young age. Illustration: iStockPhoto/Getty Images
Cancers of the colon and rectum have been declining in older adults in recent decades and have always been considered rare in young people.
However, scientists are reporting a sharp rise in colorectal cancers in millennials - adults as young as in their 20s and 30s, an ominous trend.
The vast majority of colorectal cancers are still found in older people, with nearly 90 per cent of all cases diagnosed in people over 50.
A new study from the American Cancer Society that analysed 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 are not 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.
Although 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 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’s 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 do not 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 haemorrhoids. 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 tumour 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.
Disease of aging
Most colorectal cancers are considered a disease of aging, so any increase in young adults, especially when rates of the disease are on the wane in older people, is both baffling and worrisome, experts say.
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 per cent to 2.4 per cent 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 per cent to 1.3 per cent a year since the mid-1990s.
Rectal cancer incidence rates among adults in their 20s increased even more sharply, rising by 3.2 per cent a year from 1974 to 2013.
While rectal cancer rates have declined overall among people 55 and older since 1974, rates in people 50 to 54 increased between 1989-90 and 2012-13.
By 2012-13, nearly 30 per cent of all rectal cancers were being diagnosed in people under age 55, compared with 15 per cent of all rectal cancers being found in this age group in 1989-90, the study reported.
Many patients are so young at the time of diagnosis that they have not been screened by colonoscopy, which is recommended beginning at age 50 for people who are at average risk.
The risk is higher among African-Americans, and the American College of Gastroenterology recommends they start screening at 45.
Those with colorectal cancer may experience warning signs, but the symptoms are typically vague, including general digestive complaints like diarrhoea or constipation, cramping and abdominal pain.
Tara Anderson, a 40-year-old mother of four from Bowie, Maryland, had chronic constipation for years before seeking help at a free-standing emergency room clinic in 2015 because she was in so much pain. There, a scan detected a tumour in her colon “the size of a tennis ball,” she said.
A gastroenterologist who examined her a year earlier merely told her to increase her intake of dietary fibre to ease her constipation, she said.
Fortunately, she said, her disease had not spread.
Didn’t enjoy eating
For Chris Roberts, who was 29 when he found out he had colon cancer, the first symptoms were weight loss and loss of appetite. “I lost about 20 pounds, and I wasn’t really trying to lose weight, but I just didn’t enjoy eating,” said Roberts, now 30.
He had just moved to New York City and did not have a regular doctor, but was fortunate enough to find a doctor who was determined to make a diagnosis quickly and ordered several blood tests and an ultrasound scan that found tumours that had already spread to Roberts’s liver.
He has been treated with chemotherapy and had surgery in January to remove parts of his colon and liver. “I definitely want to get the word out: If you have symptoms that may be linked to cancer, colorectal cancer or any kind, get it checked out,” he said.