Sancha Robinson was only 31 when diagnosed with stage four bowel cancer.
Dr Robinson, of Adamstown, said "I'm very lucky to still be alive".
It was almost 14 years ago that she felt a lump in her belly while having a shower.
Dr Robinson spoke about her experience for Bowel Cancer Awareness Month.
Cancer Institute NSW urged people over 45 to take five minutes to do a free screening test.
NSW chief cancer officer Tracey O'Brien said more people in NSW were now eligible to take part in bowel screening.
However, of the 6 million Australians aged 50 to 74 who were invited to do the screening in 2021-22, six in 10 didn't do the test.
Professor O'Brien said the federal government recently lowered the screening entry age from 50 to 45.
"If caught early, bowel cancer can be successfully treated in more than 90 per cent of cases," she said.
"People who do the test are almost twice as likely to have their cancer detected at the earliest stage, when it's most treatable.
"Unfortunately, Australia has one of the highest incidences of bowel cancer in the world and it's the second biggest cancer killer in NSW."
One in 14 Australians will be diagnosed with bowel cancer in their lifetime, with more than 5350 people dying from the disease a year.
The Hunter New England district recorded 3804 bowel cancer cases from 2017 to 2021, and 1362 people died from the disease in that period.
Dr Robinson said her daughter Tarryn was only eight months old when she was diagnosed.
"I was caring for her and thinking to myself my prognosis isn't very good. I'll be really lucky if I see her first birthday and go to school.
"So I'm really grateful now that I didn't leave it any longer to get that lump checked."
She quickly saw her GP, who sent her for an ultrasound.
"There were all these black blobs in my belly," she said.
A CT scan revealed the cancer had spread to her liver. She had surgery and chemotherapy.
Dr Robinson, who is an anaesthetist, learnt at university that bowel cancer "happened to old men".
"I can remember feeling really alone when it happened," she said.
"Now it seems there's more younger people getting diagnosed with bowel cancer."
She highlighted that a lump in the stomach was an unusual way to diagnose bowel cancer.
"Usually it's a change in bowel habit, or you might notice some bleeding," she said.
"I'd advocate for people getting screened for bowel cancer as soon as they can. It's really easy to do a poo test and quite easy to have a colonoscopy.
"If they can catch it early and it's just a polyp or smaller, it's much easier to deal with."
She said bowel cancer often "doesn't have many symptoms".
"So it's really worth doing that screening."
Professor O'Brien says it is a "life-saving test".
Vicki McKinnon, 68, is testament to that.
She had no symptoms when she returned a positive result in 2022.
"A subsequent colonoscopy revealed early stage bowel cancer," she said.
"Thanks to the test, the mass was operable. We caught it early before it progressed into advanced disease that required more invasive treatment.
"I tell everyone to do the test. It's easy to do and only takes a few seconds, which could save your life."
