The Distribution of PSA Age-Specific Profiles in Healthy Irish Men between 20 and 70

Background. Ireland is estimated to have the highest European incidence rate of prostate cancer (Pca) in 2006 which will increase by 275% by 2025. This study aimed to determine PSA cutoff values in different age groups of healthy male patients without Pca. Methods. 660 men in a pilot men’s health programme, aged 18–67, had PSA assayed. Men were grouped into 8 age groups at 5-year intervals: 30–34, 35–39, 40–44, 45–49, 50–54, 55–59, 60–64, and 64–70. Results. Linear regression demonstrates a PSA velocity of 0.024？ng/ml/year. The 95% confidence interval demonstrates a near flat line of PSA values from age 20 to 50 and rises after. When transformed logarithmically, PSA correlates highly with expected values from the normal distribution (0.98). A fractional polynomial quantile regression model was used to predict median and 95th percentile for PSA as follows: 30–34 (0.73, 1.57), 35–39 (0.71, 1.65), 40–44 (0.73, 1.85), 45–49 (0.78, 2.17), 50–54 (0.88, 2.63), 55–59 (1.01, 3.25), 60–64 (1.20, 4.02), and 64–70 (1.43, 4.96). Conclusions. PSA levels are similar to other racial groups but not as high as US Caucasians until 65 years. These data define the predicted PSA for the Irish population and provide a reference for future screening programmes. 1. Introduction Prostate cancer (PCa) is the most commonly diagnosed life-threatening cancer amongst men in many industrialised nations. Ireland was estimated to have had the highest PCa incidence rate in Europe in 2006 and incidence is expected to have increased by 275% between 2000 and 2025, given current trends and our ageing population. In contrast, the rate of PCa mortality among Irish men was estimated to be the tenth highest in Europe [1, 2]. Prostate-specific antigen (PSA) is a serine esterase, which is produced almost exclusively by the prostatic epithelium [3]. Its use as a tumour marker has been established for over twenty years [4]. However, it is not specific for PCa and has a high false positive rate when used as a screening tool [5]. The normal upper limit of PSA, 4.0, is not always accurate for all ages [6]. Papers have suggested that age-specific cutoff values for PSA screening are better compared than the currently used single cut-off of 4.0？ng/mL [7]. PSA may increase with prostatic hyperplasia; therefore, one would expect that the PSA level should be lower in younger men. The currently used single cut-off of 4.0？ng/mL underestimates the cancer risk in younger patients and may also result in unnecessary biopsies in older men with benign prostatic hyperplasia [8, 9]. However controversy surrounds this