Normalised repeat serum prostate-specific antigen: associations with age and magnetic resonance imaging results

Objective: To assess the value of a repeat prostate-specific antigen measurement (PSA2) before magnetic resonance imaging (MRI) in men with a raised PSA (PSA1) <10 <mu>g/L. Method: Medical records of men aged < 75 years referred in 2021 for PSA1 3.0-9.9 <mu>g/L (< 70 years) or 5.0-9.9 <mu>g/L (70-74 years) were reviewed. PSA2 was sampled before MRI within 60 days from PSA1. Odds ratios (ORs) were calculated with logistic regression. Chi-square and trend-test were used for categorical variables. Results: A total of 341 men were included. Median time between PSA1 and PSA2 was 28 days (interquartile range 20-35 days). PSA normalised in 16% (95% confidence interval [CI]: 13-21). Younger men were more likely to have a normal PSA2 (OR: 0.95 per year older, 95% CI: 0.92-0.99). Among men aged < 70 years, those with PSA1 < 5 mu g/L were more likely to have normalised PSA2 than those with PSA1 >= 5 mu g/L (21% vs. 10%, p = 0.01). A greater proportion of men with normalised PSA2 had a Prostate Imaging Data and Reporting System MRI score of 1-3 than men with non-normalised PSA2 (93% vs. 77%, p = 0.01). Conclusions: A clinically significant proportion of men with a moderately raised PSA value have a normal PSA2. Younger men and men with lower PSA1 were more likely to have a normal PSA2. Few men with normalised PSA2 had suspicious MRI findings. Routine repeat PSA-testing may be motivated in men with a moderately raised PSA value to save MRI resources, particularly in younger men.