Anterior tumors of the prostate: diagnosis and significance

Prostate biopsies are usually taken from the peripheral rather than anterior region of the prostate. Consequently, tumors originating from the anterior apical region and transition zones may be under-sampled. We examined whether addition of transrectal anterior biopsy (TAB) would improve efficacy of prostate biopsies.

Simulations of TAB and sextant biopsy (SB) were performed using computer models of 86 autopsy prostates (AP) and 40 radical prostatectomy (RP) specimens. TAB was obtained bilaterally from apex, mid, and base regions by advancing the biopsy needle 5 mm-35 mm beyond the prostatic capsule. A phase I clinical trial with 114 patients was conducted to determine the performance of an extended biopsy protocol consisting of TAB, SB, and laterally-directed biopsy (LDB).

The overall cancer detection rates of SB and TAB were 33% and 55% for AP series (p = 0.00003); 60% and 88% for RP series (p = 0.006). Alternatively, SB + bilateral apical TAB and SB + bilateral mid TAB had cancer detection rates of 45% and 42% for AP series; 80% and 78% for RP series. The extended biopsy protocol detected cancer in 33% (38/114) of patients with 29, 25, and 15 diagnosed by SB, LDB, and bilateral apical TAB, respectively. Patients diagnosed by bilateral apical TAB versus SB (p = 0.01) and LDB (p = 0.02) were statistically significant. Without bilateral apical TAB, the overall cancer detection rate decreased to 30% (34/114).

Inclusion of bilateral TAB from apical region for first time and repeat prostate biopsies may increase diagnosis of prostate cancer. The clinical significance of these findings needs further investigations and clinical follow up.