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There are notable ethnic and geographic variations in the incidence of prostate cancer.1 The highest reported incidence is from Scandinavian countries, while there is an intermediate incidence in America and the United Kingdom, and the lowest incidence occurs in the Far East, especially Mainland China and Japan.2,3
New Zealand's population consists of three major ethnic groups, New Zealand European, Maori, and Pacific Islands people and, for several years, New Zealand has ranked among the six highest incidence countries in the World.4. World Health Organization (WHO) age-standardised prostate cancer rates in 1998-1999, showed that incidence at 86.1 per 100,000, Maori males had the lowest incidence, followed by Pacific Islands males at 115.2 per 100,000, and 'other males' (chiefly New Zealand European) had the highest incidence (118.9 per 100,000).5 Conversely, the prostate cancer WHO age-standardised mortality rates for Pacific Islands and Maori males in 1998-1999 (52.3 and 39.3 per 100,000 respectively) were higher than rates for 'other males' (22.8 per 100,000).5 However, there are reported inaccuracies in ethnic health data collection in New Zealand.6
In the United States, there is a 30% higher incidence and 120% higher prostate cancer mortality rate for African-Americans, compared to European Americans.7 Indeed, most clinical studies indicate that African-American men have a two-fold higher prevalence of metastatic disease at diagnosis. Differences in tumour stage have been attributed to differences in access to and utilisation of healthcare in African-American men.8 Similarly, higher prostate cancer incidence among Japanese-American men in comparison with native Japanese men is thought to be due to the more intensive prostate cancer screening within America.9 Healthcare access and utilisation is also an issue in New Zealand for Maori and Pacific Islands people10-13 and may be reflected in the difference between prostate cancer incidence and mortality statistics shown for these groups.
When used in conjunction with a digital rectal examination, elevated PSA levels (>4.0 ng/mL) aid in the detection of organ confined prostate cancer.14 Specifically, it has been found that a PSA value between 4.0-10.0 ng/mL carries a 22% probability of prostate cancer, while a PSA value of >10.0 ng/mL increases the cancer risk to more than 60%. PSA levels can also be raised in cases of benign prostatic hyperplasia and prostatitis.15
Because of the lack of specificity and sensitivity, PSA...