"It'll particularly reduce the harm of needless intervention and it means men who have intervention are more likely to get value out of it.
"Simply put, there is little point in aggressively treating a cancer if it is unlikely to kill a man and there is no point in watching one that is certain to kill."
Wellingtonian Tom McGrath was diagnosed with prostate cancer in 2007 and said any research that helped give cancer sufferers better treatment was a good thing.
He chose to be treated by having 126 tiny radioactive seeds implanted in the gland, rather than external beam radiotherapy or surgery to remove the entire prostate.
Six years later he was declared cured and went on to write a book about his experience called Blasted by Seeds.
"When you get your diagnosis your life appears to go right out of control. You're living with uncertainty. You hope the cancer will never come back but there's still an element of risk there."
He advises men to get checked.
Men who develop prostate cancer are mostly over 65. It rarely occurs in men younger than 55. About one in 13 men will develop it before 75. In very elderly men, prostate cancer often grows very slowly and may cause no symptoms.
A Ministry of Health official said there were no plans to change the New Zealand guidelines for prostate care but the ministry regularly monitored international research to ensure New Zealanders received appropriate models of care.
University of Auckland senior research fellow Dr Helen Conaglen, who specialises in sexual dysfunction, suggests more research needs to be done into improving the quality of life of those men with prostate cancer.
"In a recent New Zealand study, 87 per cent of men who had undergone prostate cancer treatments reported changes in their sexual experience," she said.
Only 11 per cent had received counselling.
She said counselling should happen "alongside the potential changes in therapy timelines that this new stratification system offers".
Prostate cancer
• Prostate cancer is the most common cancer in New Zealand men
• There are about 3000 new cases a year
• About 600 men die from prostate cancer every year