Sensitivity and specificity of sextant biopsies in the detection of prostate cancer: preliminary report.

OBJECTIVES: To determine the true-negative and false-negative rates of sextant prostate biopsies, the most common method of prostate cancer diagnosis.
METHODS: Forty-three men scheduled for prostatectomy as part of a surgical procedure for bladder pathologic findings agreed to participate in this study. All patients had normal digital rectal examination findings. Immediately before prostatectomy all patients underwent sextant biopsies. The location, amount, and Gleason grade of any cancer identified on the biopsies were recorded. After surgery, the prostate was serially sectioned. The location, grade, and volume of any prostatic adenocarcinoma identified was recorded and compared with the results of the biopsy specimens.
RESULTS: There were 33 patients without prostate cancer in either the biopsies or the prostatectomy specimen. No patients had cancer on the biopsies and no cancer in the prostatectomy specimen. In 6 patients, cancer was found in both the biopsies and the prostatectomy specimens; these cancers were 0.9, 2.1, 2.8, 3. 1, 4.2, and 6.5 cc in volume. In the remaining 4 patients, there was no cancer on the biopsies but the prostatectomy specimen revealed cancers of 0.05, 0.1, 0.3, and 2.5 cc. The overall sensitivity for sextant biopsies was 60.0%, with a specificity of 100%. When only cancers greater than 2 cc or cancers in the peripheral zone were considered, the sensitivity rose to 83.3% and 71.4%, respectively, with a minimal decrease in specificity (97.3% and 97.2%, respectively). In contrast, when transition zone cancers were evaluated, the sensitivity fell to 33.3%.
CONCLUSIONS: Sextant biopsies are fairly sensitive for the detection of tumors greater than 2 cc and those in the peripheral zone; however, repeat biopsies should be strongly considered in patients with a high clinical suspicion for prostate cancer and negative initial sextant biopsies.