Objective: To assess impact of different prostate biopsy strategies according to prostate volume on tumor detection.
Methods: A total of 323 consecutive men with suspected prostate cancer were included in the study. Indications for transrectal ultrasound guided prostate biopsy were: abnormal digital rectal examination (DRE, 52 cases) and/or a total prostate specific antigen (PSA) over 4.0 microg/L (305 cases). In the subjects, their ages were between 49 years and 90 years, the mean: 69 years; PSAs were between 0.6 microg/L and 142.5 microg/L, the mean: 20.8 microg/L; and the prostate volumes were between 12.3 mL and 255.5 mL, the mean: 60.4 mL. Transrectal ultrasound guided prostate biopsy of 13 core scheme was conducted in each patient. The cancer detection rate for each biopsy core was calculated. The sensitivities of different combinations of biopsy cores were compared with a 13 core biopsy protocol and the prostate volumes were divided into two groups (<50 mL and >or=50 mL). The optimum number of biopsy cores was determined in patients with different prostate volumes.
Results: Of the 323 patients 120 (37.2%) were positive for prostate cancer. Compared to the patients with a prostate volume<50 mL, cancer detection rates of 13 core biopsy protocol in the patients with a prostate volume>or=50 mL decreased significantly (51.0% vs 26.1%). In patients with a prostate volume smaller than 50 mL, the 8 core biopsy protocol consisting of the apex, mid gland, base, lateral mid gland or of the apex, mid gland, lateral mid gland, lateral base of the prostate revealed the results similar to those of the 13 core biopsy protocol (sensitivities: 98.6% and 97.3%, both P>0.05). In the larger prostate volume group, 10 core biopsy protocol that included cores at the apex, mid gland, base, lateral mid gland and lateral base detected 97.6% of cancers (P>0.05).
Conclusion: Patients with larger prostates have lower cancer detection rates. For patients with prostate volume smaller than 50 mL, 8 core biopsy protocol consisting of the apex, mid gland, base, lateral mid gland or of the apex, mid gland, lateral mid gland, lateral base of the prostate can be used since it reveals results similar to those of 13 core biopsy protocol. 10 core biopsy protocol that includes cores at the apex, mid gland, base, lateral mid gland and lateral base can be used for patients with prostate volumes larger than 50 mL.