RESUMO
INTRODUCTION: To increase the detection rate of prostate cancer in recent years, we examined the increase in the number of cores taken at initial prostate biopsy. We hypothesized that an increasing number of cores may undermine the accuracy of models predicting the presence of prostate cancer at initial biopsy in patients submitted to 20-core initial biopsy. METHODS: A total of 232 consecutive patients with prostate-specific antigen (PSA) between 4 and 20 ng/mL and/or abnormal digital rectal examination (DRE) underwent 12-core prostate biopsy protocol (group 1) or 20-core prostate biopsy protocol (group 2). The patients were divided into subgroups according to the results of their serum PSA and prostate volume. We evaluated the cancer detection rate overall and in each subgroup. Clinical data were analyzed using chi-square analysis and the unpaired t-test or 1-way ANOVA with significance considered at 0.05. RESULTS: The 2 groups of patients were not significantly different with regard to parameters (age, abnormal DRE and serum PSA), although median prostate volume in group 1 (57.76 +/- 26.94 cc) were slighter greater than in group 2. Cancer detection rate for patients submitted to 20 prostate biopsy was higher than patients submitted to 12 prostate biopsy (35.2% vs. 25%, p = 0.095). Breakdown to PSA level showed a benefit to 20 prostate biopsy for PSA <6 ng/mL (37.1% vs. 12.9%, p = 0.005). Stratifying results by prostate volume, we found that the improvement of cancer detection rate with 20 prostate biopsy was significant in patients with a prostate volume greater than 60 cc (55% in 20 prostate biopsy vs. 11.3% p < 0.05). Morbidity rates were identical in groups 1 and 2 with no statistically significant difference. There appeared to be no greater risk of infection and bleeding with 20 prostate biopsy protocol. CONCLUSION: The 20-core biopsy protocol was more efficient than the 12-core biopsy protocol, especially in patients with prostate specific antigen <6 ng/mL and prostate volume greater than 60 cc.
