The percentage of affected fragments in needle biopsy in the assessment of pathological staging of prostate cancer

INTRODUCTION: Prostate cancer has high prevalence and mortality among men. Some of the findings on prostate biopsy may be related to the prognosis of the disease. OBJECTIVE: To evaluate the association between the percentage of fragments affected by cancer in the prostate biopsy and the pathological staging in the surgical specimen. MATERIALS AND METHODS: Selected 159 patients underwent radical prostatectomy (RP) between 2003 and 2009. Data was collected on age, digital rectal exam, prostate-specific antigen (PSA), Gleason score, number of biopsy fragments, number of fragments affected by tumor, and tumor extension in the surgical specimen. Statistical analysis with Student's t-test, chi-squared test, and multiple logistic regression evaluated the association of percentage of affected fragments (PAF) with tumor extension and its predictive value. RESULTS: The patients mean age and PSA were respectively 64 years and 8.5 ng/ml. Histopathologic evaluation of surgical specimens revealed 20.8% of patients with extraprostatic disease, 8.2% with seminal vesicle invasion and 35.8% with positive margins. We found that patients with extraprostatic disease, positive surgical margins, and seminal vesicle invasion had a higher mean PAF. PAF was divided into three groups: less than 34%, 34% to 50%, and greater than 50%, and the higher the PFA, the larger the increase in pathological changes. CONCLUSION: PAF in biopsy is a simple and practical parameter, which should be used as a predictor of pathological stage in RP specimen.