Transrectal ultrasonography for the early diagnosis of adenocarcinoma of the prostate: a new maneuver designed to improve the differentiation of malignant and benign lesions.

Abstract

Transrectal ultrasound can reveal potentially malignant prostate lesions while they are still small. However, based on ultrasound alone they are often difficult to distinguish from benign focal lesions. We tested the reliability of a new technique for the sonographic evaluation of typical prostate lesions in differentiating adenocarcinoma from benign lesions. During 18 months 398 consecutive male patients 45 to 76 years old underwent transrectal ultrasound for the early detection of prostate cancer. When suspicious hypoechoic lesions were noted in the peripheral regions of the prostate, moderate pressure was applied on the lesion using the ultrasound probe to evaluate consistency. Based on the response lesions were classified as deformable (the shape changed from approximately spherical to oval) or nondeformable (the original shape was retained). All lesions were then diagnosed based on fine needle biopsy. Peripheral hypoechoic prostate lesions were sonographically identified in 146 of 398 patients (36.7%). In 68 cases nondeformable lesions proved to be adenocarcinoma in 63 (92.6%), and chronic prostatitis and/or adenomatous hyperplasia in 5. In contrast, 62 of the 78 deformable nodules (79.5%) showed histological features of hyperplasia and/or chronic inflammation. The remaining 16 nodules, which showed more limited changes in shape during compression, were characterized by hyperplasia with acute inflammatory changes. In 5 cases there was also evidence of adenocarcinoma. Ultrasound guided compression of suspicious prostate lesions detected on transrectal sonography is a simple, rapid and reliable maneuver that may increase the diagnostic potential of this examination.