Transrectal Ultrasound-Guided Prostate Biopsy: Sextant versus 12-Core Protocol

In Nigeria, prostate cancer is the most diagnosed cancer in males from middle age. The only definitive way to confirm prostate cancer is through prostate biopsy. Transrectal ultrasound (TRUS)-guided core needle biopsy of the prostate has become the procedure of choice for obtaining high-quality tissue cores for histopathologic assessment in patients with suspected prostate cancer. Successive biopsy protocols have emerged to improve the detection rate of prostate cancer while maintaining its safety and tolerability.

This study aimed to compare cancer detection rates between sextant and extended 12-core biopsy protocols using TRUS-guided needle biopsy amongst patients being evaluated for prostate cancer in Lagos University Teaching Hospital, Lagos.

This study was a prospective comparative hospital-based study involving patients evaluated for prostate cancer. All study participants had thorough clinical evaluation, including digital rectal examination, a serum assay for prostate-specific antigen (PSA), radiologic imaging of the prostate with TRUS and TRUS-guided extended 12-core needle biopsy of the prostate (including six-sextant and six-lateral core biopsies). Samples obtained were sent separately for histological analysis. Data analysis was performed using the Statistical Package for Social Sciences^® version 22. The cancer detection rate of sextant and extended 12-core biopsies was compared, and the relationship to the clinical, radiologic, and histologic findings was analysed using Fisher's exact test, Kruskal-Wallis test, and McNemar correlation as appropriate. The significance level (P value) was set at 0.05.

In total,138 men (aged 37-89 years) were enrolled in this study and had extended 12-Core TRUS-guided prostate needle biopsy. In total, 78 men (58.2%) tested positive for cancer, 52 men had benign prostatic hyperplasia (BPH), and four men had prostatitis. Of the 78 patients positive for prostate cancer, six-sextant biopsy protocol detected 61 (78.2%), and six-lateral-directed biopsies detected 77 (98.7%), showing an improvement of 17 (20.5%) of six-lateral biopsies over six-sextant biopsy protocol. This was statistically significant (P < 0.001). The extended 12-core biopsy protocol (combination of the two techniques) shows an overall improvement of 18 (21.8%) in cancer detection over the sextant protocol alone, which was also statistically significant (P < 0.001). The study showed that the extended 12-core biopsy protocol was significantly superior in detecting cancer of the prostate than the sextant six-core biopsy protocol.

This study showed that men with prostate cancer were older, had smaller prostates, and had higher PSA range levels. Increasing the number of cores taken on prostate biopsy is associated with an increase in cancer detection rate, as the extended 12-core biopsy protocol outperformed the conventional sextant protocol significantly. The improvement in detection rate was most marked in lower PSA ranges ≤20 ng/mL. Screening modalities for prostate cancer had better predictive value for prostate cancer detection in their combination.