And here's the longer view: "Colorectal cancer risk among millennials has escalated back to the level of those born" circa 1890, says lead study author Rebecca Siegel in a statement picked up by Live Science. They found that colon cancer rates have been increasing by one to two percent each year from the mid-1980s through 2013 in adults 20- to 39-years-old.
The American Cancer Society recommends lowering your risk of colon cancer by eating lots of fruits, vegetables and grains, cutting down on red meat and processed foods, exercising and limiting how much alcohol you drink.
Opposing trends in young and older adults over two decades have closed a previously wide gap in disease risk for people in their early 50s, compared to those in their late 50s.
For years, overall rates of colon and rectal cancers have been dropping for the people thought to be most at risk-the elderly.
"If they are particularly concerned about their individual risk of colorectal cancer, for example, if they have a family history of the disease, they should talk to their doctor about whether to start screening earlier", he said.
In the mid-1990s, the rates of colon cancer increased in adults in their 40s (1.3 percent each year) and adults ages 50 to 54 (0.5 percent each year), the researchers also observed.
Her study was based on patient data on more than 490,000 people in the US Surveillance, Epidemiology, and End Results (SEER) program registries.
Most of the nation's 135,000 annual cases and 50,000 deaths related to colon and rectal cancer still occur among people over age 55.
"This new study would favour a closer look at whether screening should be done earlier", said Dr John Kisiel, a gastroenterologist at the Mayo Clinic in Rochester, Minnesota.
There has been significant interest to do more research in this area, with this group of patients that we wouldn't normally expect to be diagnosed with cancer at such a young age.
They point out in 2013 in the USA, 10,400 new cases of colorectal cancer (CRC) were diagnosed in people in their 40s, with an additional 12,800 cases diagnosed in people in their early 50s. Starting in about 1974, the rate has been increasing by about 3 percent a year among people aged 20 to 29.
In 40 to 54 year olds, rectal cancer rates increased by 2% per year from the 1990s.
"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", said Siegel.
The disease is still far less common in twenty-somethings than in older people, with about 1 case in every 100,000 people, but Ms Siegel said the rising incidence could point to higher rates in the future.