Fig. 1.

Graph showing PSA level (ng/mL) plotted against age (both measured at the prostate check clinic).The lines depict the three thresholds of PSA which may trigger further investigations (i) a threshold of PSA = 3 ng/mL for all ages (--- line); (ii) NICE thresholds (age 50–59: PSA = 3 ng/mL; age 60–70: PSA = 4 ng/mL; age ≥ 70: PSA = 5 ng/mL) (-- -- -- line); (iii) age-specific threshold developed in the current study above which the fastest increasing 2.5% of men lie (solid line). The performance of the threshold depends on the age distribution of the data so the graphs have been stratified by age group. A random sample of men were plotted to improve readability. X indicates a man diagnosed with clinically significant prostate cancer (1 in 200 men plotted, n = 406). A dot indicates a man not diagnosed with prostate cancer or with prostate cancer at low risk of progression (1 in 100 men, n = 813). An upper bound for age-specific PSA level, above which the fastest increasing 2.5% of men lie, can be estimated using the PSA level for each age as described by the Krimpen study [8]. The plotted points, where age (years):PSA(ng/mL), are: 50:2.8, 51:3.0, 52:3.2, 53:3.4, 54:3.6, 55:3.8, 56:4, 57:4.2, 58:4.6, 59:4.9, 60:5.2, 61:5.6, 62:6.1, 63:6.5, 64:7, 65:7.6, 66:8.3, 67:9, 68:9.8, 69:10.4, 70:11.3