The areas with the lowest diagnostic rates in the entire state – Toorak and the Melbourne CBD – are located in the inner city. These areas have diagnostic rates 22 per cent and 21 per cent lower than the national average, respectively.

Medical oncologist Dr Prasad Cooray said while bowel cancer risk increased with age, it was also important for people to understand that the disease didn’t affect only older populations.

“I see athletes, marathon runners, the healthiest young people – and they get bowel cancer, too.”

Cooray said doctors did not fully understand why regional areas had higher rates of bowel cancer.

The traditional thinking is that people are at higher risk if they have an inflammatory bowel condition, like Crohn’s disease, or a family history of bowel cancer. Physical inactivity, eating a lot of red or processed meat, high alcohol consumption, smoking and type 2 diabetes are also considered risk factors.

“On the other hand, younger onset bowel cancer patients do not have those risk factors or have not lived long enough for those factors to become causative,” Cooray said.

“So, it’s becoming increasingly accepted that there are other risk factors. Maybe those play a bigger role in regional areas. Could it be chemicals used in farming? Could it be something else? We haven’t gotten to that level of granularity.

“Unless we actually collect the data and look at this in a serious way, we won’t know.”

In Melbourne, the suburb with the highest rate of bowel cancer diagnosis is Wallan, on the city’s northern fringe, where rates are 10 per cent higher than the Australian average.

Ann Capling – who lives in Kew, an area with a lower-than-average rate of bowel cancer diagnosis – was shocked when she received a letter from the National Bowel Screening Program saying her screening test had returned a positive result.

It was 2017, and the then 58-year-old professor had been using the free screening test kits since her early 50s, assuming everything was normal.

“I was in good health, Mediterranean diet, no history of bowel cancer in the family and no symptoms,” Capling said.

The professor followed up with her doctor, who referred her to a gastroenterologist for a colonoscopy. During the procedure, the gastroenterologist removed a cancerous polyp which, if left undetected, could have developed into bowel cancer.

“I was really grateful because if I hadn’t done the test they sent in the mail, it could have been years before the symptoms developed and then the cancer [would have been] really advanced. Then you’re facing surgery, radiation and chemotherapy, so I was very lucky.”

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Capling, now 66, said the free screening tests were a “no-brainer” for people in her age group.

“It takes 30 seconds. You’ll either have enormous peace of mind for two more years, or you’ll have the huge benefit of detecting the cancer early.”

Cancer Council head of screening Kate Broun said bowel cancer was the second-biggest cause of cancer death and the third most diagnosed cancer in Victoria. However, if detected early, more than 90 per cent of such cancers could be successfully treated.

“For people aged 45 to 74, the best way to find bowel cancer early is by doing the free bowel screening test kit as soon as it comes in the mail,” Broun said. “The test is simple and doing it every two years can save your life.”

People are advised to be physically active, eat healthier – including more fibre – and quit tobacco to reduce their bowel cancer risk.

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