The government is being told to lower the age for the bowel cancer screening programme to 45.
Bowel Cancer New Zealand says there are unacceptable barriers to diagnosing bowel cancer and wants the age limits lowered for screening.
Medical advisor Professor Frank Frizelle said it was increasingly becoming a younger person's disease.
It was estimated that in 10 years one in every 10 colon cancers and one in every five rectal cancers will be in those aged under 50, he said.
"Research shows colon cancer has risen by 14 percent in men and rectal cancer by 18 percent in men under 50 alone in the past decade," Frizelle said in a statement.
It was often very difficult for those people to get screened, he said.
More than 3000 New Zealanders are diagnosed with bowel cancer and 1200 die from the disease each year - 350 of those diagnosed are under 50.
Many patients were facing unacceptable delays due to waiting time deferments and lack of resources, exacerbated by staffing shortages due to Covid-19, he said.
"Right now many GPs have valid concerns that younger patients they refer for public hospital investigation will be denied assessment due to their youth and perceived lower risk," he said.
Covid-19 had discouraged patients from symptoms from visiting their GP, increased already long waiting lists for investigative colonoscopies, seen operating lists cancelled and put pressure on hospital staff, he said.
Bowel Cancer NZ general manager Rebekah Heal said for Māori, 22 percent of bowel cancers were picked up when they were aged in their 50s, so it was vital to prioritise lowering the screening age for them.
"We mustn't forget that Aotearoa New Zealand has a high rate of bowel cancer, costing as many lives as breast and prostate cancers combined," she said in a statement.
If you are aged between 60-74, screening for bowel cancer is free and can be done at home. More information about the national programme can be found here.
Guidance on how to do the test can be found here.
'A silent creeper'
Anna Heritage-Sao was 32 years old when she found out she had the disease after her lower back pain turned out to be a tumour.
She was not aware of bowel cancer symptoms at the time but a random series of events led to her diagnosis.
"When I reflect back on my symptoms, you know, I've had haemorrhoids before so blood in my stool wasn't uncommon for me, I made excuses for the other symptoms I had in terms of inconsistency in stools again can be put down to haemorrhoids, the feeling of not completely emptying your bowel, of fatigue - I was really busy with a project at work at the time," Heritage-Sao said.
"So I'd made excuses for the symptoms I'd been having and passed it off."
But after ending up in the emergency department, a kidney stone was discovered which led to a CT scan as a precaution.
"I went in, thinking nothing of it, and within an hour of leaving Auckland hospital for the CT scan, my GP was ringing me to ask me to go and see him," Heritage-Sao said.
"And so they had seen a shadow in my bowel and that was bowel cancer. A couple of weeks after that, I was having surgery to remove the tumour."
Heritage-Sao counts herself lucky because the system acted quickly and the tumour was detected in its early stages, meaning she only had to get surgery.
But she said she understood that was not always the case in the health system.
"You're never too young ... it wasn't even on my radar at the time so when I was told I had this tumour, I was like 'what?' Apart from having those symptoms, I was operating absolutely fine, I felt normal, I felt healthy.
"I guess that's the scary thing about bowel cancer, it's a silent creeper, I had this tumour growing inside me and I had no idea.
"Even when I walked into the operating theatre and laid on the table, even at that point I was like 'are you sure this is inside me? Like I feel absolutely normal, absolutely fine'."
She said she was seeing more young people suffering from bowel cancer.
"It really breaks my heart and a lot of them have similar cases to me, where they just didn't even think cancer was an option at this age. But that's the scary thing, cancer doesn't discriminate on anything, especially on age."
Sometimes there is shame or whakamā behind discussing bowel symptoms, but Heritage-Sao said in hindsight, talking about that would be easier than talking about your diagnosis to loved ones.
"I come from a Pasifika background and it can be whakamā, it can be embarrassing to talk about things, especially talking about these symptoms, but at the end of the day, it's your life that's on the line.
"When I think about the difficulty of having a conversation like this, talking about your symptoms or your poo and how your poo looks and feel and all the rest of it, compared to the conversation that I've had to have with my parents and my family when I told them I'd been diagnosed ... I'd rather have the conversation about poo upfront and prevent it."