The sextant protocol for ultrasound-guided core biopsies of the prostate underestimates the presence of cancer

Abstract

Objectives: The aim of this prospective study was to evaluate the sensitivity of the sextant biopsy protocol compared with a more extensive procedure for the detection of prostate cancer and to define a biopsy model with the minimal number of biopsies necessary to maintain diagnostic accuracy.

Methods: A total of 512 consecutive patients with suspected prostate cancer were examined with transrectal ultrasound (TRUS) and underwent TRUS-guided core biopsy. All patients had 8 or 10 standardized biopsy samples taken, with the number depending on the size of the gland. Additional biopsy samples were taken from hypoechoic or hyperechoic lesions located outside the predetermined location for the standardized biopsies (ie, target biopsies). The sensitivity of the detection of cancer for different combinations of biopsy samples was analyzed and compared with that of our model with 8 to 10 biopsies.

Results: In all, 276 cancers were detected, of which 88 (32%) had an isoechoic appearance. Sensitivity was 59% for focal lesions detected by TRUS, 85% to 97% for different combinations of systematic biopsy samples, and 93% to 98% for a combination of systematic and target biopsy samples. The sensitivity for the standard sextant protocol was 85%. By adding target biopsies, the sensitivity increased to 93%.

Conclusions: The standard sextant protocol leaves 15% of cancers undetected compared with results obtained from a more extensive biopsy procedure. By combining systematic and target sampling, the sensitivity increases; however, a major concern is that the clinical importance of cancers detected by multiple biopsies needs to be evaluated.