Many abnormal PSA test results normalize over time

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J Fam Pract. 2003 September;52(9):664-688

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BACKGROUND: PSA is frequently used for prostate cancer screening. Positive screening values often lead to biopsy and other invasive interventions, but the long-term natural history of PSA levels is not known.
POPULATION STUDIED: The researchers studied PSA levels of men previously enrolled in a dietary intervention trial to reduce the recurrence of colon polyps (Polyp Prevention Trial, 1991–1998). The trial included men aged >35 years having a colon adenomatous polyp removed within 6 months of the trial.
STUDY DESIGN AND VALIDITY: This is a descriptive, 4-year longitudinal cohort from a randomized controlled trial conducted between 1991 and 1998. The researchers analyzed PSA results from frozen blood samples collected in the original trial at baseline and at four 1-year intervals. Previous work demonstrated acceptable long-term stability of frozen total PSA.
OUTCOMES MEASURED: The study measured PSA levels (ng/mL) at the following clinical standards: total PSA >2.5, total PSA >4.0, age-specific total PSA levels, free/total PSA <0.25, or PSA velocity >0.75.
RESULTS: For the criterion of total PSA >2.5, 37% of men had at least 1 positive value. Among the 291 [317] men with an abnormal value and at least 1 remaining blood draw, 40% [36%] had values return to the normal range on at least 1 subsequent occasion. For 62 [88] men who had at least 2 subsequent blood draws remaining, 65% [45%] had 2 consecutive normal levels.

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