The Predictive Value Of Transrectal Ultrasound Combined With Elastography In Benign And Malignant Prostatic Lesions

Background and ObjectiveProstate cancer (PCa) as one of the common malignant tumors among elderly men, ranks the second in the male cancer death rate. It has a high incidence in Europe and the United States, but in recent years, due to the trend of an aging population, its incidence in China is also increasing year by year. Prostate cancer occurs often with hidden signs, its early clinical symptoms are fairly similar to that of prostatic hyperplasia, and its most cases are found too late. Therefore, an accurate and early detection of prostate cancer is an urgent priority. Real-time tissue Elastography (RTE) techniques, as a new technology established on the basis of conventional ultrasound imaging, has added to more useful information in the application of thyroid and breast cancer detection, while it has been rare in the application of prostate disease in domestic reports. This technique is based on the principle that different pathological structures reflect different organization hardness information.This paper mainly aims to evaluate the predictive value of Transrectal Ultrasound combined with Real-time Tissue Elastography in diagnosing benign and malignant prostate lesions according to the gold standard of pathology and the comparison with serum prostate specific antigen (PSA) and Magnatic Resonance Imaging (MRI).Objects and Methods1. We evaluated82patients with prostate hyperplasia or suspicious PCa from October2011to December2012in the second affiliated hospital of Zhengzhou University. A total of108lesions were included. Both TRUS (Transrectal Ultrasonography) and TRTE (transrectal real-time tissue elastography) examination were performed. All of the lesions went through biopsy guided by TRTE and confirmed by pathology. The sonographic features of prostatic lesions were described and the differences between benign and malignant lesions by sonographic features were compared with pathology.2. The receiver operating characteristic curve (ROC) for strain ratio (SR) and elastic grading was drawn according to the pathologic results, the best cut-off of SR was set and the area under curve was calculated.3. Regarding the elastic grade I-II as benign and III-V as malignant lesions, the diagnostic performance was compared with pathologic findings after TRTE guided biopsy. For the malignant lesions, the elastic grading was compared with pathological Gleason grade results.4.68lesions had complete clinical data of TRTE, TRUS, PSA and MRI. Considering pathology as the gold standard, the diagnostic accuracy of TRTE+TRUS was compared with PSA and MRI examination in the differential diagnosis of benign and malignant prostatic lesions.Results1. As a result,48benign lesions and60malignant lesions were confirmed by pathology. Take the pathology results as golden standard, differences between benign and malignant groups based on TRTE elastic classification method were compared statistically significant (Z=-5.005, P=0.000).2. The best cut-off of SR on ROC curve for diagnosing PCa was2.900, area under the curve was0.937. The sensitivity and specificity was87.51%and88.92%, respectively. There was significant difference between benign lesions and PCa based on the SR (Z=-7.062, P<0.001).3. For malignant lesions, there was a positive correlation between pathological Gleason grading and elastic grading, Spearman rank correlation coefficient (rs) was0.5599(χ2=14.4223, P=0.0001). The SR was2.95±0.71for the group of Gleason grading5～6,4.11±0.44for that of Gleason grading7, and4.91±0.59for that of Gleason grading8～10. There was statistical difference among the three groups (F=22.590, P=0.000).4. In the sonographic features of prostate focus contrasted with pathologic results, the location, boundary, shape, internal echogenicity, blood flow grading and the elastic grading were statistically significant in the identification of benign and malignant lesions (P<0.05), while the characteristic of blood flow resistance index was without statistical significance in the identification of benign and malignant (χ2=4.370, P=0.224).5. TRTE and TRUS had no statistical difference in the diagnosis of benign and malignant prostatic lesions (χ2=0.0345, P=0.8527); The diagnosis accuracy of TRUS+TRTE was significantly higher than that of TRTE (χ2=7.852, P=0.049) or TRUS (χ2=8.000, P=0.046) respectively.6. The accuracies of TRTE+TRUS, serum PSA and MRI in differential diagnosis of benign and malignant prostatic lesions were83.82%,76.47%and82.35%respectively. No difference was found between TRTE+TRUS and MRI (%2=0.0370, P=0.0370), the accuracy of TRUS+TRTE was higher than PSA (x2=8.5263, P=0.0035).Conclusions1. The predictive value for prostate benign and malignant lesions by TRTE combined with TRUS is higher than the serum PSA screening, and is more economic and feasible than MRI. The elastic classification and SR complement each other provide a new technical means for the differential diagnosis of benign and malignant lesions of the prostate.2. For the malignant prostate lesions, Ultrasonic elastography classification and pathology Gleason grading have some positive correlation, to some extent, it can be used to guide the PCa prognosis.3. The puncture under the guidance of TRTE can significantly improve the accuracy in the location of prostate lesions and reduce the false positive and false negative rate of prostate biopsy. TRTE make the previous guidance by TRUS more targeted.