Korean J Urol.  2006 Dec;47(12):1284-1288. 10.4111/kju.2006.47.12.1284.

Biological Variation of Serum Prostate Specific Antigen Levels in Men Aged 50 or Older without Prostate Cancer

• Kim JY
• Cho JS
• Kwon MS
• Jang WS
• Park SY
• Chung BS
• Kang HJ

• KMID: 2139772
• DOI: http://doi.org/10.4111/kju.2006.47.12.1284

Abstract

PURPOSE
To evaluated the effect of the intra-individual variation in the serum prostate specific antigen (PSA) level in men without prostate cancer to decide on the requirement of a prostate biopsy.
MATERIALS AND METHODS
Patients, aged between 50 and 80 years, were screened for prostate cancer or lower urinary tract symptoms at least 2 times within 3 months using PSA or free PSA measurements. Patients with an initial PSA level between 2.0 and 10.0ng/ml were included. Those with prostate cancer, urinary tract infection or 5-alpha reductase inhibitor medication were excluded. The coefficient of variation (CV) was evaluated in each PSA range.
RESULTS
The analysis included 139 patients, with a mean age 62.1 years. The level of free PSA was measured in 56 patients. The mean interval between the two PSA measurements was 36.6 days. The mean CVs for the total PSA and % free PSA were 21.5 and 22.2%, respectively. 20% of patients show a CV of more than 30%, implying a large variation. In our study, the 95% confidence interval of initial PSA levels between 3.0 and 4.9ng/ml included the PSA cut-off point (4.0ng/ml) in the visit results.
CONCLUSIONS
The variation the PSA level was relatively small, but some patients showed a CV greater than 30%. Therefore, the intra-individual PSA variation should become part of interpreting the PSA test results, especially for men with a PSA value near the cut-off point.

Keyword

Prostate-specific antigen; Antigen variation; Prostate

MeSH Terms

Antigenic Variation
Biopsy
Humans
Lower Urinary Tract Symptoms
Male
Oxidoreductases
Prostate*
Prostate-Specific Antigen*
Prostatic Neoplasms*
Urinary Tract Infections
Oxidoreductases
Prostate-Specific Antigen

Figure

• 

  Fig. 1 The relationship between the initial and next visit prostate-specific antigen (PSA) results. The solid line is obtained from a linear regression analysis.

• 

  Fig. 2 Distribution of the coefficient of variation for the total prostate-specific antigen serum concentration.

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