Needle Biopsy Sampling Techniques and Role of Multiparametric-Magnetic Resonance Imaging Modality in Prostate Cancer Diagnosis and Management

The clinicopathological characteristics of newly diagnosed prostate cancer have significantly changed due to widespread prostate-specific antigen (PSA) screening after its introduction in the late 1980s. The most remarkable change has been “stage migration” toward smaller volume disease at a younger age. The diagnosis of prostate cancer now is mostly triggered by an elevated or rising PSA rather than an abnormal digital rectal examination, resulting in a significant increase in the percentage of nonpalpable cancers (stage T1C) between 1988 and 1996 from 10% to 73%. With this trend, the prostate biopsy application and sampling techniques have also rapidly evolved. In 1989, the transrectal ultrasound (TRUS)-guided sextant prostate biopsy was introduced and rapidly became the standard over directed biopsies of hypoechoic lesions and palpable nodules. In recent years, it has become increasingly evident that sextant biopsies could miss a significant number (up to 30%) of cancers because only a small percentage of prostates has a tumor distribution detectable with the paramedian template utilized by the sextant approach. Furthermore, sextant protocol tends to undersample certain areas of the prostate, such as “anterior horns” and the lateral aspects of the peripheral zone, where majority of prostate cancer arises. Recent studies suggested moving the biopsies more laterally to better sample the lateral aspects and anterior horns of the peripheral zones. This recommendation was supported by the zonal anatomy of the prostate as well as the origin of the tumor. Because approximately 80% of prostate cancers originate in the peripheral zone, extended biopsy templates that more extensively sample this region could improve the cancer detection rate.