Comparison of unrestricted targeted biopsy to targeted sextant biopsy of the prostate

Abstract

Objective: Recent studies have demonstrated improved detection of prostate cancer with targeted biopsy using microbubble contrast agents. We evaluated cancer detection with two different contrast-enhanced biopsy strategies: unrestricted targeted biopsy of the most suspicious areas in the outer gland, and targeted sextant biopsy of the most suspicious area within each sextant.Methods: One hundred eighteen subjects with an elevated PSA (>4 ng/ml) or abnormal digital rectal examination were evaluated by transrectal sonography during infusion of a microbubble contrast agent (Imagent: Alliance Pharmaceuticals). Up to 4 unrestricted targeted biopsy cores were directed toward the most suspicious area(s) of the outer gland during contrast-enhanced harmonic gray scale and Doppler imaging. Six additional biopsy cores were obtained in a modified sextant distribution to target the most suspicious area within each sextant. Any sextant with no suspicious area was sampled with a laterally directed core.Results: Cancer was detected in 145 biopsy cores from 35 of 118 subjects (30%). Among 57 subjects with no previous biopsy, the cancer detection rate was 40% (23/57). Cancer was found in 15% (65/432) of unrestricted targeted cores and in 11% (80/704) of targeted sextant cores. Of 35 subjects with cancer, 28 were detected by both techniques. Six subjects were detected only by targeted sextant biopsy, whereas 1 subject was detected only by unrestricted targeted biopsy. Although 40% (32/80) of positive targeted sextant cores were obtained at the gland apex, only 17% (11/65) of positive unrestricted targeted cores were obtained from the gland apex. Among 432 unrestricted targeted biopsy cores, only 18% (80) were directed to the apex.Conclusions: Although the per-core cancer detection rate of unrestricted targeted biopsy was slightly higher when compared to the targeted sextant approach, the unrestricted technique missed cancers at the apex of the prostate. The low proportion of targeted biopsy cores in the apex suggests that contrast enhancement is less conspicuous at the apex. To maximize cancer detection, we recommend that any contrast-enhanced biopsy strategy must include targeted cores of the prostatic apex. Objective: Recent studies have demonstrated improved detection of prostate cancer with targeted biopsy using microbubble contrast agents. We evaluated cancer detection with two different contrast-enhanced biopsy strategies: unrestricted targeted biopsy of the most suspicious areas in the outer gland, and targeted sextant biopsy of the most suspicious area within each sextant. Methods: One hundred eighteen subjects with an elevated PSA (>4 ng/ml) or abnormal digital rectal examination were evaluated by transrectal sonography during infusion of a microbubble contrast agent (Imagent: Alliance Pharmaceuticals). Up to 4 unrestricted targeted biopsy cores were directed toward the most suspicious area(s) of the outer gland during contrast-enhanced harmonic gray scale and Doppler imaging. Six additional biopsy cores were obtained in a modified sextant distribution to target the most suspicious area within each sextant. Any sextant with no suspicious area was sampled with a laterally directed core. Results: Cancer was detected in 145 biopsy cores from 35 of 118 subjects (30%). Among 57 subjects with no previous biopsy, the cancer detection rate was 40% (23/57). Cancer was found in 15% (65/432) of unrestricted targeted cores and in 11% (80/704) of targeted sextant cores. Of 35 subjects with cancer, 28 were detected by both techniques. Six subjects were detected only by targeted sextant biopsy, whereas 1 subject was detected only by unrestricted targeted biopsy. Although 40% (32/80) of positive targeted sextant cores were obtained at the gland apex, only 17% (11/65) of positive unrestricted targeted cores were obtained from the gland apex. Among 432 unrestricted targeted biopsy cores, only 18% (80) were directed to the apex. Conclusions: Although the per-core cancer detection rate of unrestricted targeted biopsy was slightly higher when compared to the targeted sextant approach, the unrestricted technique missed cancers at the apex of the prostate. The low proportion of targeted biopsy cores in the apex suggests that contrast enhancement is less conspicuous at the apex. To maximize cancer detection, we recommend that any contrast-enhanced biopsy strategy must include targeted cores of the prostatic apex.