The relationship between prostate volume and prostate-specific antigen variability: Data from the Baltimore Longitudinal Study of Aging and the Johns Hopkins Active Surveillance Program

OBJECTIVE: • To clarify the relationship between serial prostate-specific antigen (PSA) variability and prostate volume in both cancer-free participants from the Baltimore Longitudinal Study of Aging (BLSA) and patients with low-risk prostate cancer from the Johns Hopkins Active Surveillance Program (AS). MATERIALS AND METHODS: • In all, 287 men from the BLSA and 131 patients from the AS were included in the analysis, all with at least two PSA measurements and concurrent prostate volume measurements. • PSA variability was calculated in ng/mL per year, and a linear mixed-effects model was used to determine the relative effects of prostate volume, baseline PSA and age on PSA change over time. RESULTS: • In a model with prostate volume, age and baseline PSA, there was no significant relationship between prostate volume and PSA variability (BLSA, P = 0.57; AS, P = 0.49). • Only baseline PSA showed a significant relationship to PSA yearly variability (PSAYV) (P < 0.001). Specifically, a one unit higher baseline PSA (ng/mL) corresponded on average to 0.09 and 0.06 ng/mL per year higher PSAYV in the BLSA and AS populations, respectively. CONCLUSIONS: • The results of the present study suggest that the primary driver of PSA variability is the baseline PSA level, rather than prostate volume. • Clinicians might consider the baseline PSA level to help predict the expected variability in serial PSA measurements.