Prostate-specific antigen and age. Is there a correlation? And why does it seem to vary?

Abstract

To determine whether there is a significant correlation between age and prostate-specific antigen (PSA) and to explain the wide literature variations in its value. Two different groups were studied; the first (n = 403) consisted of patients undergoing prostatectomies for symptomatic benign prostatic hypertrophy (BPH) and the second (n = 192) of patients with no evidence of prostate cancer who required no treatment. The correlation coefficient found in the surgical group was low (0.09) and was statistically insignificant while in the second group it was much higher (0.36) and had a high statistical significance (p < 0.001). This reflected the age difference between the two groups rather than the difference in clinical characteristics as proved by the gradual decrease in the value of the coefficient by the gradual exclusion of the younger age groups. The correlation became statistically insignificant for those older than 60 years. It is concluded that the correlation between age and PSA is a variable one showing a gradual decline in its coefficient with the gradual increase in the age of the population studied. This implies a relatively orderly rise in PSA with age up to a limit of 60 years. Beyond this age, the relationship between age and PSA becomes disorderly. This pattern of relationship can easily be explained by the known rate of growth of BPH and would explain the literature variations.