Purpose: It has been previously demonstrated that a prostate specific antigen velocity greater than 2 ng/ml per year is associated with reduced cancer specific survival following radical prostatectomy or external beam radiation. However, men with different initial prostate specific antigen levels may be more or less likely to reach this prostate specific antigen velocity threshold. Because prostate specific antigen and prostate specific antigen velocity contain much of the same predictive information, our objective was to further examine the relationship between them.
Materials and methods: From a large prostate cancer screening study, serial prostate specific antigen measurements were available for 13,276 men, including 1,851 with a negative digital rectal examination who underwent biopsy and 894 who were diagnosed with prostate cancer. Prostate specific antigen velocity was calculated using simple linear regression of the prostate specific antigen values from the year before diagnosis. ANOVA and the Kruskal-Wallis test were used to compare the mean and median prostate specific antigen velocity of men in different total prostate specific antigen ranges. In addition, chi-square analysis was used to compare the number of men in each total prostate specific antigen range who presented with high risk prostate specific antigen velocity greater than 2 ng/ml per year.
Results: In the total prostate specific antigen ranges of 2.5 ng/ml or less, 2.6 to 4.0, 4.1 to 10.0 and more than 10.0 ng/ml, the proportion of screened men with a prostate specific antigen velocity of more than 2 ng/ml per year was 1%, 14%, 31% and 74%, respectively (p <0.0001). Mean and median prostate specific antigen velocity were also significantly higher as the total prostate specific antigen level increased.
Conclusions: Prostate specific antigen velocity varies directly with total prostate specific antigen. Men with high initial prostate specific antigen levels are significantly more likely to present with a prostate specific antigen velocity of more than 2 ng/ml per year that is more frequently associated with prostate cancer specific mortality.