Controversy regarding Diagnosis and Staging of Prostatic Carcinoma: The Role of Rectal Exploration and Imaging Methods

Abstract

Although rectal examination (RE) represents the most utilized diagnostic tool, its reliability is limited by the large number of false positive results (low sensitivity) which” limit its use as a screening method. Transrectal ultrasound (TRUS) is very useful in the diagnosis of prostatic neoplasms, as the hypoechoic lesions are very likely to be cancerous and should be biopsied. Nevertheless tumoral hypoechogenicity is not specific and at most only 1 of 3 hypoechoic areas in the peripheral and central zones will prove to be cancer. Of palpable stage B cancers in the peripheral and central zones, 21% are reported to be isoechoic. Moreover cancers that arise in the transitional zone cannot ever be detected as hypoechoic tumors because of the heterogenic echo texture of this zone filled with diffuse hypoechoic nodules of BPH. The integration between RE, TRUS and PSA improves diagnostic accuracy. As far as neoplasm staging is concerned the proper evaluation of the Gleason score and spatial distribution of the tumor are referred by some authors to be assured only by means of “systematic” biopsies of the two prostatic lobes, independently of the echographic support. RNM and CT do not assure a better diagnostic or staging reliability, while endorectal RM is considered to afford, in comparison with TRUS, a better visualization of periprostatic structures and therefore a more reliable evaluation of neoplastic extracapsular extension.