RESUMEN
<p><b>OBJECTIVE</b>To determine the distribution characteristics of cancerous foci in the prostate by retrospective analysis on the radical prostatectomy (RP) samples from patients with prostate cancer diagnosed by single positive core biopsy and treated by RP.</p><p><b>METHODS</b>Thirty-seven patients with prostate cancer diagnosed by ultrasound-guided biopsy and single positive core biopsy underwent RP. We reviewed the pre- and post-operative data of the patients, compared the results of biopsies and pathological examination of the RP samples, and analyzed the factors that led to the underestimation of the overall prostate cancer risks.</p><p><b>RESULTS</b>Post-operative pathological results showed multifocal distribution of the tumors in 70% of the patients (26/37) and obviously increased Gleason score (7-9) in 56% (21/37). The clinical stages of the tumors had been significantly underestimated preoperatively. The underestimation of their clinical stages might be due to a larger proportion of cancer tissues in a single positive core biopsy, and that of the overall cancer risks attributed to PSAD > 0.2 microg/L. Larger prostate volume (> or = 40 ml) increased the possibility of multifocal distribution.</p><p><b>CONCLUSION</b>The risk of prostate cancer diagnosed by single positive core biopsy might be underestimated, and the cancerous foci were characterized by multifocal distribution in the prostate.</p>