Failure of Focal Prostate Cancer on Biopsy to Predict Focal Prostate Cancer: The Importance of Prevalence

Abstract

Purpose We investigated whether the reported correlation between focal prostate cancer on biopsy and the presence of clinically insignificant cancer applies to men with an elevated serum prostate specific antigen level or a positive biopsy from an area of palpable abnormality. Materials and Methods A total of 33 men with these findings and focal cancer on biopsy underwent radical perineal prostatectomy, with step-section pathological analysis of all specimens and volume determination of all stage pT2a tumors. Results Pathological examination revealed that 17 tumors (52 percent) were stage T3, 10 (30 percent) stage T2b to c and 6 (18 percent) stage T2a, with 4 (12 percent) significant (volumes 0.8 to 1.2 ml.) and 2 (6 percent) insignificant (volumes 0.1 and 0.3 ml.) neoplasms. Thus, focal prostate cancer on biopsy correlated with significant cancer in 94 percent of the cases. Conclusions In patients with another variable controlling for a high prevalence of significant prostate cancer, the focal nature of a positive biopsy probably refects only sampling limitations and should not influence treatment. To restrict prostate biopsy to men with a high prevalence of significant cancer, targeted area biopsy alone must replace sextant biopsy in men with a palpable prostatic abnormality but a normal prostate specific antigen level.