Study Type – Prognosis (retrospective cohort analysis)
Level of Evidence 2b
What's known on the subject? and What does the study add?
PSA screening reduces prostate cancer mortality but also may lead to unnecessary biopsies and overdiagnosis of insignificant tumours. PSA velocity (PSAV) risk count (number of serial PSAV exceeding 0.4 ng/ml/year) significantly improves the performance characteristics of screening for overall prostate cancer and high-grade disease on biopsy. Risk count may be useful to reduce unnecessary biopsies and prostate cancer overdiagnosis compared to PSA alone.
- • To determine whether the prostate-specific antigen velocity (PSAV) risk count (i.e. the number of times PSAV exceeds a specific threshold) could increase the specificity of screening for prostate cancer and potentially life-threatening tumours.
PATIENTS AND METHODS
- • From 1989 to 2001, we calculated two serial PSAV measurements in 18 214 prostate cancer screening-study participants, of whom 1125 (6.2%) were diagnosed with prostate cancer.
- • The PSAV risk count was determined as the number of PSAV measurements of >0.4 ng/mL/year (0, 1, or 2).
- • We used receiver operating characteristic (ROC) and reclassification analyses to examine the ability of PSAV risk count to predict screen-detected and high-grade prostate cancer.
- • The PSAV was >0.4 ng/mL/year twice (risk count 2) in 40% of prostate cancer cases compared with only 4% of those with no cancer (P < 0.001).
- • After adjusting for age and PSA level, a PSAV risk count of 2 was associated with an 8.2-fold increased risk of prostate cancer (95% confidence interval 7.0–9.6, P < 0.001) and 5.4-fold increased risk of Gleason score 8–10 prostate cancer on biopsy.
- • Compared with a model with age and PSA level, the addition of the PSAV risk count significantly improved discrimination (area under the ROC curve 0.625 vs 0.725, P= 0.031) and reclassified individuals for the risk of high-grade prostate cancer (net reclassification, P < 0.001).
- • Sustained rises in PSA indicate a significantly greater risk of prostate cancer, particularly high-grade disease.
- • Compared with men with a risk count of ≤1, those with two PSAV measurements of >0.4 ng/mL/year (risk count 2) had an 8-fold increased risk of prostate cancer and 5.4-fold increased risk of Gleason 8–10 disease on biopsy, adjusting for age and PSA level.
- • Compared to PSA alone, PSAV risk count may be useful in reducing unnecessary biopsies and the diagnosis of low-risk prostate cancer.