Indications for extended 14-core transrectal ultrasound-guided prostate biopsy

We compared the cancer detection rate of extended 14-core biopsy with that of sextant biopsy to assess whether additional biopsy cores are useful for detection of prostate cancer and to clarify the indications for obtaining additional cores.

Study subjects were 313 patients who underwent transrectal ultrasound-guided 14-core biopsy because of a prostate-specific antigen (PSA) level greater than 4.0 ng/mL and/or abnormalities found on digital rectal examination (DRE). In addition to the standard 6 biopsy cores, 6 lateral cores were obtained as well as 2 transition zone cores. PSA density (PSAD) was determined as the total PSA level divided by the prostate volume as estimated by transrectal ultrasound.

Prostate cancer was diagnosed in 127 patients (40.6%). In 28 (22%) patients, the cancer would not have been detected by the sextant method alone. Among 211 patients with normal DRE findings, the cancer detection rate with 14-core biopsy was statistically higher than that with 6-core biopsy in the 141 patients with a PSA level of 4.01 ng/mL to 10.0 ng/mL, and 14 (38.9%) of 36 cancers were diagnosed in additional cores only, not in the standard sextant biopsy cores. Among the 141 patients with a gray-zone PSA level, the cancer detection rate with extended biopsy was statistically higher in those with PSAD greater than 0.13 ng/mL.

Lateral biopsy should be used in conjunction with sextant biopsy in patients with a PSA level of 4.01 ng/mL to 10.0 ng/mL with normal DRE findings, especially in those with PSAD greater than 0.13 ng/mL.