The correlation between PSA doubling time (PSADT) and need for definitive intervention has been debated. In the May issue of the Journal of Urology, Dr. Jared Whitson and colleagues from UCSF interrogate their database to determine if an association exists between PSA change and biopsy progression in these patients.
Patients met USCF inclusion criteria for AS if they had Gleason score ≤6 CaP in 33% of cores with no core >50%, PSA <10ng/ml and clinical stage T1-2. Patients had PSA followed at 3-month intervals and repeat 12-core prostate biopsies every 12-18 months. Mathematical modeling demonstrated that a PSADT of 3 years or less correlated to a PSA velocity (PSAV) ≥0.231ng/ml/yr. They adjusted for covariates. They identified 241 patients from their database of 408 patients who met study criteria. They found a relevant difference among included vs. excluded men in that the included group more commonly underwent the initial prostate biopsy at outside facilities. The greater likelihood for CaP upgrading in these patients suggests that the study cohort was at greater risk for biopsy progression. They identified only one patient to have PSADT >3 years (2.7 years). Seven men had a 50% decrease in PSA within 3 years. Initial repeat prostate biopsy occurred in 55 men (23%) at a median followup of 10 months; 46 (19%) had an increase in Gleason score, 11 (5%) had an increase in percent positive cores to greater than 33%, and 12 (5%) had an increase in the single positive core percentage to >50%. The untransformed unadjusted PSAV was 0.02ng/ml/yr in men without progression and -0.016 in men with progression. The one patient with PSADT <3 years did not have progression on prostate biopsy. PSADT <3 years correlated with 1.4-fold increased odds of biopsy progression. They found that older patients had significantly increased odds of biopsy progression, but patients with higher stage CaP and longer times between biopsies had a non-significant increase.
They concluded that it was surprising how little change occurred in PSA during the study period, resulting in a lack of statistical association between PSAV and biopsy progression but still having clinical relevance.
Whitson JM, Porten SP, Hilton JF, Cowan JE, Perez N, Cooperberg MR, Greene KL, Meng MV, Simko JP, Shinohara K, Carroll PR
J Urol. 2011 May;185(5):1656-60