New Zealand men are being diagnosed with prostate cancer later in life with a higher prostate-specific antigen (PSA) level and higher disease grade compared to men in the United States according to University of Auckland research

Dr. Nishi Karunasinghe and colleagues at the Auckland Cancer Society Research Centre at the University's Faculty of Medical and Health Sciences compared prostate cancer data from New Zealand and the US.

The study, in conjunction with clinicians from the Auckland City Hospital and academics from the Laboratory of Human Carcinogenesis, National Cancer Institute in Maryland, has just been published in PLOS One.

In New Zealand, 408 men were recruited for the study from Auckland DHBs between 2006 and 2013. In the US, 976 men recruited and were either African American or European American.

In the US, 31-36% of men have been PSA screened between 2000 and 2010. In New Zealand, there was no dedicated prostate screening system in place and PSA testing or digital rectal examination or both were undertaken at varying levels (7-41%) by primary care physicians

Diagnosis

The current study shows that New Zealand men are diagnosed at a mean age of 66 years, compared to 62 years for the African Americans, and 64 years for European Americans. Even our median PSA and median grade at cancer detection is higher than that of both African and European Americans.

"The cumulative high-risk prostate cancer detection variation with increasing PSA levels shows that our high-risk prostate cancers are detected at higher PSA levels compared to the US men," says Dr. Karunasinghe.

She says the figures are even worse among patients that smoke, either currently or in the past as smoking could impact delayed diagnosis particularly among those with certain genotypes that are more common in M?ori and Pacific men. Dr. Karunasinghe says the results are also more concerning for M?ori and Pacific men as more of them tend to smoke compared to European New Zealand men.

"Several factors including lower levels of PSA screening, delayed referral to specialist care and lower subsequent biopsies on those with elevated PSA levels compared to that of US could be underlying reasons for this discrepancy that require attention from the New Zealand health authorities."

In New Zealand, prostate cancer is the most commonly registered male cancer and the third most common cause of cancer deaths. In the US, it is the most common cancer in men after skin cancer and the second leading cause of cancer death.