Prostate-specific antigen levels in men aged 70 years and over: Findings from the champ study

Measurement of serum prostate specific antigen (PSA) levels is not recommended for universal prostate cancer screening but it still remains a useful diagnostic tool, when utilised in an individualised way.

PSA reference ranges for men from various ethnic backgrounds were recently published, based on systematic review and meta-analysis of forty-three studies conducted between 1993 and 2018.

Clear age-related increases in PSA reference values were observed, resulting in pooled upper limits of 2.1, 3.2, 4.9 and 6.5 ng/ml for men aged 40-49, 50-59, 60-69 and 70-79 years, respectively.

However, ethnic differences in PSA levels suggest this should also be considered to guide diagnosis.

Reference ranges for Australian men aged over 70 years, published more than 20 years ago, remain relevant but they are likely of decreasing utility, because for these men, “the harms of PSA testing may be greater than the benefits of testing in men of their age”.

Background

PSA screening for prostate cancer in unselected populations remains controversial due to the limited data on benefits, and significant risks of over-diagnosis and over-treatment.

It is generally acknowledged that older men (the US guidelines state over 75 years) will not benefit from screening but it appears that many older Australian are having PSA tests.

PSA levels increase with age such that age-specific reference ranges could help to increase the specificity of the test. However, there are few population-based PSA studies that include old men, or the numbers of men in older age groups are small.

It is also known that PSA levels vary across ethic groups, an issue of importance in the ethnically diverse Australian population.

Aim

To describe values of serum prostate-specific antigen (PSA) in older men without diagnosed prostate cancer, categorised by age and country of birth, and to describe self-reported prostate cancer screening.

Methods

The Concord Health and Ageing in Men Project (CHAMP) is a cohort study involving a representative sample of 1434 eligible community-dwelling men with no diagnosis of prostate cancer who were aged between 70 and 97 years of age and living in a defined geographic area in Sydney.

Baseline data were collected between January 2005 and June 2007.

Serum PSA levels were measured at baseline. Information on self-reported PSA testing and/or digital rectal examination (DRE), age, country of birth, and the International Prostate Symptom Score (IPSS) was collected in a baseline questionnaire that included other demographic and health variables.

Results

Eleven per cent of men (n=155) had a PSA level of ≥ 6.5 ng/mL (the suggested cut-off for further investigation for men aged 70 or over, from an American study), increasing from 7.5% of men aged 70–74 years to 31.4% of men aged ≥ 90 years.

PSA levels varied with country of birth: Australian-born men (n=695) had the highest levels (median, 2.3 ng/mL; 5th–95th percentile, 0.4–10.1 ng/mL), followed by men born in China (n = 42; 2.1 ng/mL; 0.4–12.4 ng/mL), United Kingdom and Ireland (n = 70; 1.9 ng/mL; 0.3–8.9 ng/mL), Greece (n = 59; 1.5 ng/mL; 0.2–6.1 ng/mL), and Italy (n = 293; 1.4 ng/mL; 0.3–7.2 ng/mL).

A PSA test in the previous 2 years was reported by 48% of participants, and a digital rectal examination (DRE) in the previous 2 years by 37%.

Men with moderate to severe lower urinary tract symptoms (defined by IPSS scores) were more likely to have a PSA test while a lower education level and being born in China (compared to Australia) were associated with a lower likelihood of having PSA testing.

Conclusion

A significant number of men aged over 70 years reported recent prostate cancer tests.

The PSA level ranges, according to age and country of birth, reported in this cohort will help with interpreting serum PSA level findings in men aged over 70 years.