Association of changing prostate-specific antigen (PSA) levels on repeat testing with lower risk for Gleason Score (GS) ≥ 7 prostate cancer

• 284 Background: PSA levels are often verified before recommending a prostate biopsy because of the variability of PSA, We used data from the STHLM3 trial to assess the value of a second PSA test taken prior to biopsy. Methods: STHLM3 is a prospective and population-based prostate cancer diagnostic study performed in Stockholm, Sweden, 2013-2015. 1686 men in STHLM3 with a PSA value 3-10 ng/ml performed a second PSA test within 8 weeks of the first test and then underwent prostate biopsy. We compared proportions of cancer detected in men with stable PSA levels (2nd PSA within +/-10% of 1stPSA) to men whose PSA levels increased or decreased at least 10%, respectively. Results: Men with GS ≥ 7 cancer in the biopsy had more stable PSA than men with benign biopsies; the median change was 13.7% (inter-quartile range (IQR) 6.1-26.9) in men with benign biopsies, 13.0% (IQR 6.1-25.6) in men with GS ≤ 6 tumors and 8.2% (IQR 4.5-16.7) in men with GS ≥ 7 tumors. The average risk of having GS ≥ 7 cancer was 15.4% (95% CI 13.7 – 17.1) after the first test (i.e. the entire cohort), 21.6% (95% CI 18.6 – 24.6) in men with stable PSA levels compared with 13.5% (95% CI 10.2 – 16.7) and 9.0% (95% CI 6.6 – 11.4) if PSA levels increased or decreased at least 10%, respectively. There were no significant differences in risk of GS ≤ 6 tumor for men with stable PSA compared to men with increasing/decreasing PSA. Conclusions: As previously shown, the risk of prostate cancer decreases if a repeat PSA test shows decreasing levels. We show that this effect mainly affect GS ≥ 7 tumors, and that the risk of prostate cancer also decreases with increasing PSA values. Our findings need validation, but suggest that PSA is more stable in men with GS ≥ 7 cancer, whereas elevated but fluctuating PSA levels to a higher degree are caused by other processes (e.g. inflammation). Use of decision tools could aid incorporation of complex information such as repeat PSA values in diagnostics.

Publication and Content Type

vet (subject category)

kon (subject category)