Impact of added biopsy areas on prostate cancer detection: preliminary analysis.

OBJECTIVE

To evaluate variations in prostate cancer detection relevant to the number and areas of biopsy cores.

METHODS

Ninety patients with elevated prostate-specific antigen levels, abnormal physical examination findings, or both had ultrasound examinations plus biopsies. Forty-nine patients had 11 biopsies, and 41 patients had 6 biopsies. The numbers of cancers detected were compared on a patient-by-patient basis and by all biopsy sites grouped together. An analysis of the relationship between a positive gray scale sonographic finding and the presence of adenocarcinoma was done.

RESULTS

On a patient-by-patient basis, 43% of patients who had 11 biopsies had adenocarcinoma. In patients who had 6 biopsies, 32% had adenocarcinoma. Thirty-eight percent of the additional cancers found in the 11-biopsy group were in 5 additional areas not sampled in the 6-biopsy group. Of the total of 539 biopsy specimens obtained in the 11-biopsy group, 56 (10%) had adenocarcinoma; 43% of these 56 were positive in the 5 additional areas not sampled in the 6-biopsy group. No statistical differences (P > .05) were found for mean age, mean prostate-specific antigen level, and mean volume in the groups with 11 and 6 biopsies. This indicated that the observed difference was not related to any of these factors. Similar pathologic data were found for patients with prostatic intraepithelial neoplasia.

CONCLUSIONS

Our data indicate the added value of additional biopsy sites over the usual 6 biopsies to increase the yield of adenocarcinoma and prostatic intraepithelial neoplasia detected. The added biopsy sites of the central and midperipheral glands were areas where additional specimens positive for adenocarcinoma and prostatic intraepithelial neoplasia were obtained.