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KMID : 0356420070250030123
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Journal of Korean Andrology
2007 Volume.25 No. 3 p.123 ~ p.128
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Delta Prostate Specific Antigen (PSA) Helps to Predict Prostate Cancer in Men with Serum PSA Level above 4 ng/ml
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Park Bong-Hee
Park Jung-Sun
Park Jong-Kwan
Park Kyeong-Soo
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Abstract
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Purpose: Prostate biopsies have typically been performed on all patients with prostate specific antigen (PSA) levels above 4 ng/ml, however, the cancer detection rate is low. We would like to predict cancerous conditions of the prostate by developing a new PSA formula.
Materials and Methods: Between July 2004 and July 2006, 93 patients with serum PSA levels above 4 ng/ml received extended prostate biopsies. The medical records of all patients - age, total/free PSA after/before prostate
massage, final diagnoses of prostate biopsies - were reviewed retrospectively. We developed a new formula to calculate the delta PSA: (total/free PSA after prostate massage - total/free PSA before prostate massage) / total/free PSA before prostate massage.
Results: The patients were divided into two groups, the prostate cancer group (39 patients) and the benign disease group (54 patients). Mean total/free PSA for the benign disease group were 9.35/1.49 ng/ml (before) and 16.66/5.06 ng/ml (after), while values for the data of prostate cancer group were 21.02/2.43 ng/ml (before) and 24.61/4.40 ng/ml (after). The positive predictive value of the patients with PSA levels between 4 and 10 ng/ml was 32%; the positive predictive value of the patients with PSA levels above 10 ng/ml was 75%. The mean delta total/free PSA values for the benign disease and prostate cancer groups were 0.92/2.42 and 0.28/1.14, respectively. The cut off value of delta total/free PSA was below .5/2.0. Sensitivity, specificity, and positive predictive values for delta total PSA were 90% (95% confidence interval (CI), 80.2∼99.3), 54% (95% CI, 41.4∼67.7) and 58% (95% CI, 45.9∼70.8), respectively. Sensitivity, specificity, and positive predictive values based on delta free PSA were 87% (95% CI, 76.7∼ 97.7), 48% (95% CI, 36.7∼63.3), and 56% (95% CI, 43.3∼68.2), respectively.
Conclusions: We suggest that the use of delta total/free PSA in patients with serum PSA levels above 4 ng/ml may be helpful, not only to better detect prostate cancer, but also to reduce unnecessary prostate biopsies.
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KEYWORD
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Prostate-specific antigen, Prostate cancer, Detection
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