Grim cancer diagnosis spurred Tim, 72, to tackle 8 marathons

He would run five kilometres.

But he didn't stop there - in his healthy ambition lead him to complete the The Canberra Times' half-marathon and he hasn't looked back.

Mr O'Meara, who lives in Cobargo on the NSW South Coast, said he's taken it easy since then by only tackling a mere "six to eight" full marathons and an ultramarathon.

His partner Allison Allwood attributes the drive to hit the pavement from boredom while undergoing radiation treatment in Canberra.

"He doesn't read or watch TV, he doesn't like sitting still, basically. He was really bored up there. So he started walking; the walking turned into jogging," she said.

Running feels like "freedom" for Mr O'Meara, and despite the cancer prognosis he is unbelievably fit.

"It's bloody amazing. He ran the Stromlo 50km trail run last November. It was just amazing," Ms Allwood said.

"He comes up after the marathons, and most people are just collapsing [but] Timmy walks 2km home to where he's staying. It's extraordinary."

Aside from running three times a week and going to the gym, Mr O'Meara mows lawns in order to fund his hobby.

Mr O'Meara will be running 42.2km at The Canberra Times' marathon festival on April 7.

Prostate cancer is estimated to account for 28 percent of the cancers to be diagnosed in males for the year in 2023, according to the Australian Institute of Health and Welfare.

While there is no single test to detect it, the prostate specific antigen (PSA) blood test can indicate the possibility of the cancer.

Mr O'Meara said he had taken the tests for several years before his general practitioner noticed an elevation off his baseline.

He had an aggressive form of prostate cancer which Ms Allwood said wouldn't have caused symptoms until it was too late.

"If not for the blood test, he would not have shown symptoms until he was stage four. Just that small dip into the PSA and the doctor [was] getting on to it really early," she said.

"Not all cancers impinge on the urethra, so you don't get any urinary symptoms until it's there.

"If we hadn't gotten into on to it very early, Timmy would be in a very different state now."

Mr O'Meara wants all men to start getting their prostate specific antigen blood levels tested.

"Hopefully this will get people to go and be checked," he said.

Prostate cancer mostly affects people aged 50 and above.

After non-melanoma skin cancer, it is the most common cancer in Australian men.

There is a 96 per cent five year survival rate.

The Cancer Council says that while an elevated PSA can indicate prostate cancer, "two-thirds of cases... are due to noncancerous conditions".

"Overdiagnosis of prostate cancer can lead to unnecessary treatments that have side effects such as sexual impotence, urinary incontinence and bowel problems."