Prediction of the extent of prostate cancer by the combined use of systematic biopsy and serum level of cathepsin D.

Abstract Background: The objective of this study was to assess the usefulness of combined systematic prostate biopsy with the serum level of cathepsin D, which has recently been shown to be a useful marker for prostate cancer, to predict the disease extension. Methods: Seventy-two patients with clinically organ-confined disease who underwent radical prostatectomy were evaluated for serum prostate-specific antigen (PSA) and cathepsin D levels, systematic biopsy, and pathological stage. Results: The incidence of extraprostatic disease in patients with more than half the biopsy cores positive or ≥ 15 ng/mL cathepsin D was significantly higher than that in patients with less than half the biopsy cores positive or < 15 ng/mL cathepsin D, respectively; whereas cancer in bilateral lobes or ≥ 10 ng/mL PSA could not be used as a predictor of extraprostatic disease. Furthermore, in patients with more than half the biopsy cores positive and ≥ 15 ng/mL cathepsin D or those with more than half the biopsy cores positive and ≥ 10 ng/mL PSA, extraprostatic disease was significantly more common than in those with less than half the biopsy cores positive and < 15 ng/mL cathepsin D or those with less than half the biopsy cores positive and < 10 ng/mL PSA, respectively. Furthermore, the prediction of the incidence of extraprostatic disease using these three variables was significantly more accurate than using two of the variables (percentage positive biopsy cores plus serum cathepsin D or PSA). Conclusion: Systematic biopsy together with serum cathepsin D and/or PSA was a useful predictor of the extent of prostate cancer. Patients with more than half the biopsy cores positive, ≥ 15 ng/mL cathepsin D and/or ≥ 10 ng/mL PSA could avoid prostatectomy because there is a significantly high probability that they already have extraprostatic disease. [ABSTRACT FROM AUTHOR]