To determine the utility of systematic biopsy alone or combined with an assay of serum prostate-specific antigen (PSA) level to predict the extent of prostate cancer in Japanese men.
Patients and methods
Thirty-two patients who were diagnosed as having clinically organ-confined prostate cancer and who underwent prostatectomy were evaluated retrospectively for the results of systematic biopsy (percentage of positive biopsy cores and cancer location), serum PSA and the pathological stage of whole-mount sections of the prostatectomy specimens.
The incidence of extraprostatic disease (pT3N0M0 or N+) in patients with ≥ 8 ng/mL of serum PSA and cancer in bilateral lobes was significantly higher than in those with <8 ng/mL PSA and cancer in one lobe (83% vs 30%, P=0.020). In those with more than half the biopsy cores positive, extraprostatic disease was significantly more common than in those with less than half positive (93% vs 44%, P=0.0075); moreover, in patients with more than half the cores positive and ≥ 8 ng/mL serum PSA, it was significantly more common than in those with less than half positive and <8 ng/mL of serum PSA (93% vs 27%, P=0.0021). However, the incidence of extraprostatic disease predicted by three variables (cancer location, percentage positive biopsy cores and serum PSA) was not significantly better than that predicted by two variables (percentage positive cores and serum PSA).
The combination of systematic biopsy and serum PSA may be useful in predicting extraprostatic cancer. Patients with ≥ 8 ng/mL serum PSA and more than half the biopsy cores positive could avoid a prostatectomy because there is a high probability that they have extraprostatic disease.