Almost half of the colorectal cancers in Canada are discovered after they've already spread, even though most provinces and territories have screening programs that can catch it in early stages, according to new statistics released Wednesday.

The report by the Canadian Cancer Society says about 29 per cent of colorectal cancers are diagnosed at stage 3, and 20 per cent are diagnosed at stage 4.

One of the report's authors, epidemiologist Leah Smith, said early detection is key to boosting survival rates, but relatively few people seem to be taking advantage of organized screening programs, including an at-home stool test that can detect pre-cancerous signs.

Most colorectal cancer screening programs in Canada use the fecal immunochemical test, or FIT, according to the Canadian Cancer Society. The test uses antibodies to detect whether or not blood is present in stool samples. (CBC)

The five-year survival rate when diagnosed at stage 4 is less than 15 per cent. The rate increases to 90 per cent when colorectal cancer is found at stage 1.

The Canadian Cancer Society recommends that everyone between the ages of 50 and 74 who are not at high risk for colorectal cancer should be screened every two years.

People at higher risk (including those with a family or personal history of colon cancer, people who have had non-cancerous polyps in the colon or rectum or who have inflammatory bowel disease) may need to be tested more often and at an earlier age.

"Early detection for this disease is key," said Smith, who is the society's senior manager of surveillance. "We have the tools available to detect these cancers earlier. Unfortunately, what we're also seeing is that participation in colorectal cancer screening is lower than we need it to be to really make a move on this cancer."

Early detection through screening for colorectal cancer is key to surviving it, says Leah Smith, senior manager of surveillance at the Canadian Cancer Society. (Canadian Cancer Society)

Nine provinces and Yukon territory currently have organized colorectal cancer screening programs that use at-home stool tests, and plans are underway to develop programs in Nunavut and Quebec. Northwest Territories does not have an organized screening program but stool tests are available through hospitals and clinics.

The tests are used to detect blood in the stool. If blood is found, then the person goes for followup tests, such as a colonoscopy or barium enema, so a doctor can check the colon and rectum.

Smith said Canadians aged 50 to 74 years of age make up about one-third of the population and should do the stool screening, but researchers found less than 60 per cent of those eligible for the test are doing so.

'How can you not do this?'

Singer-songwriter Jeff Orson said that after he was diagnosed with stage 2 colorectal cancer, he began urging those around him to get tested.

"How could you not go; how can you not do this? If it's in your family, especially, you're at risk, it's easily preventable," said the 56-year-old performer, based in Oakville, Ont.

Orson said he was lucky to catch the cancer early when he went to his doctor complaining of feeling exhausted and losing sleep. Because he was in his 50s, he was sent for a stool test, which came back positive. That led to a colonoscopy, which revealed a tumour in his colon.

"That was one of the most horrible things I ever heard in my life: 'You have cancer and we don't know what your future holds for you,"' he recalled.

Surgeons removed 18 centimetres of his colon and Orson has been cancer-free for four years.

Now he undergoes regular colonoscopies and blood tests and doesn't shy away from sharing his story on his website, and onstage during performances.

"It's like a shadow, it never kind of leaves you," he said. "I don't dwell on it a lot but every day I'm thankful that I get up."

(Canadian Cancer Society )

Colorectal cancer is the second most commonly diagnosed cancer in Canada and the second leading cause of cancer death, after lung cancer.

It is estimated that about one in 13 men and one in 16 women will be diagnosed with colorectal cancer during their lifetime.

An estimated 26,800 Canadians were diagnosed with colorectal cancer in 2017, representing 13 per cent of all new cancer cases, while 9,400 Canadians died from the disease, representing 12 per cent of all cancer deaths.

Simply put, fewer Canadians would die from this disease if more were screened, Smith said.

She noted that more than 80 per cent of breast cancers are found at stage 1 or 2, likely due to screening. As a result, breast cancer survival rates are 87 per cent compared to lung cancer, which are closer to 17 per cent. About half of lung cancers are found at stage 4.

"It really helps reinforce that connection between early detection and survival," Smith said.

Wednesday's study was gathered in partnership with the Public Health Agency of Canada and Statistics Canada.