Tekin, A. et al. Post-prostatic massage examination for prediction of asymptomatic prostatitis in needle biopsies: a prospective study. J. Urol. 182, 564–569 (2009).
Men with elevated serum PSA levels usually undergo prostate biopsy to rule out malignancy. A new study has shown that the most common non-cancer diagnosis—asymptomatic prostatitis—can be made reliably by determining leukocyte number in a sample of urine collected after prostatic massage. The currently applied cut-off value of <10 leukocytes per high power field (HPF) might, however, be too high, according to the authors.
Ali Tekin and colleagues from Istanbul, Turkey, assert that using microscopic examination of post-prostatic-massage urine to screen men with a mildly elevated PSA level and a normal digital rectal examination could reduce the number of unnecessary biopsies. “Leukocyte count in post-prostatic-massage urine may be clinically useful for screening and identification of asymptomatic prostatitis before biopsy, which may enhance the specificity of PSA,” notes Tekin.
...using microscopic examination of post-prostatic-massage urine ... could reduce the number of unnecessary biopsies
His team prospectively evaluated 161 men with a PSA level between 4 and 10 ng/ml, no apparent symptoms of prostatitis or infection, and no abnormalities detected during digital rectal examination. All consented to collection of a post-prostatic-massage urine sample, as well as to biopsy.
Histological review of prostate tissue samples confirmed the presence of cancer in 20% of patients, benign prostatic hyperplasia in 39%, and prostatitis in 41%. There were significant differences in leukocyte number between the three groups, with higher counts registered for men with subclinical prostatitis. A leukocyte threshold of <5 cells per HPF was the most accurate predictor of prostatitis.
“If biopsy had been done only in subjects without prostatitis, based on a leukocyte count of <5 per HPF in post-prostatic-massage urine, unnecessary biopsies [would have been] avoided in 45% of men with benign histology, while the diagnosis of prostate cancer would have been missed in 12.5%,” states Tekin. He suggests that the currently used cut-off of <10 leukocytes per HPF is too high.
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Senior, K. Urine leukocyte threshold for detection of subclinical prostatitis too high. Nat Rev Urol 6, 462 (2009). https://doi.org/10.1038/nrurol.2009.161
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DOI: https://doi.org/10.1038/nrurol.2009.161