Typically, prostate cancer occurs more frequently as men age into their 70s or 80s.
Many prostate cancers are slow-growing and many older men diagnosed with early stage prostate cancer will end up dying from causes other than prostate cancer, researchers said.
But, the researchers found, when prostate cancer strikes at a younger age, it's likely because the tumour is growing quickly.
"Early onset prostate cancer tends to be aggressive, striking down men in the prime of their life. These fast-growing tumours in young men might be entirely missed by screening because the time-frame is short before they start to show clinical symptoms," said Kathleen A Cooney, professor of internal medicine and urology at the University of Michigan.
They will be looking at whether these younger men are more likely to have inherited genetic mutations.
Men with a family history of prostate cancer have a two- to three-times greater chance of being diagnosed with prostate cancer. That risk increases for young men with multiple affected relatives.
The new analysis found that men with early onset prostate cancer had more genetic variants than men diagnosed with prostate cancer at a later age.
The study was published in the journal Nature Reviews: Urology.
