New research confirms there is a rising tide of adults under the age of 50 developing cancers of the colon and rectum in seven countries, including Canada.

Researchers with the World Health Organization examined the rates of colorectal cancers among 143 million people in seven high-income countries (Australia, Canada, Denmark, Norway, New Zealand, Ireland, and the U.K.) and found the presence of the diseases has declined overall in the past 10 years, but has increased dramatically among those under the age of 50.

Colorectal cancer refers to both colon and rectal cancer. It is the third-most common cancer in the world, with 1.8 million new cases reported worldwide in 2018.

The findings, recently published in The Lancet, showed a 3.4 per cent increase in colorectal cancer among Canadians younger than 50 and a decrease of 1.9 per cent among those aged 50 to 74. The study indicates the increases are more prominent among women and girls.

Such is the case for Christine Benson, a 38-year-old from Port Hope, Ont., who was diagnosed with Stage 3 colon cancer two years ago.

“I think (the doctors) were definitely surprised just because of my age, and I didn’t have any family history,” she told CTV News. “They were definitely shocked and I was more shocked.”

For Dr. Shady Ashamalla, a surgical oncologist at Sunnybrook Health Sciences Centre in Toronto who specializes in colorectal cancer among younger patients, the study is a confirmation of what he sees on a regular basis.

"My youngest patient was 18 but I have managed patients in their late teens, a number in their 20s and a staggering number in their 30s and 40s," he said.

Researchers speculate obesity, red meat consumption, smoking and physical activity could all be to blame for the increases in colorectal cancer among young people, but add further study is needed to confirm these assumptions. For Benson, having no real explanation is troubling.

“The main concern is that nobody seems to be able tell us why, or where it’s coming from,” she said. “People would say: ‘You eat well and you’re fit and you exercise,’ and I don’t really have any parts of my lifestyle that would lead cancer to come into my life. That’s a little bit concerning.”

In Canada, screening for colorectal cancer generally begins at age 50, but researchers suggest reviewing the guidelines to bring screening to people at a younger age. They also suggest people should remain vigilant at any age—-and look for any changes in bowel movements, signs of rectal bleeding or a lump in their abdomen, all of which are potential symptoms of colorectal cancers.

"(We need) vigilance from each individual person to address their symptoms, look at their stool, to not be shy about bringing changes in stool or their bowel habits to their doctors, and getting them investigated,” Ashamalla said. “The earlier we treat this disease the better results we get.”

Ashamalla added doctors play a role in keeping an eye out for the symptoms among their younger patients and the treatments need to be tailored to younger patients.

“We need to take those symptoms just as seriously in a 35-year-old as we would in a 60-year-old,” he said. “Understanding what’s abnormal and understanding that abnormal could mean colorectal cancer despite a patients age and investigating it accordingly.”