Factors influencing the degree of enhancement of prostate cancer on contrast-enhanced transrectal ultrasonography: correlation with biopsy and radical prostatectomy specimens

Objectives: This study was designed to identify factors that influenced the degree of enhancement of prostate cancer on contrast-enhanced transrectal ultrasonography (CETRUS). Methods: 139 patients suspected of prostate cancer were evaluated with CETRUS followed by systematic and targeted transrectal ultrasound-guided biopsies. The degree of enhancement of the lesions was objectively measured using peak intensity with time-intensity curve analysis software. Ultrasound findings were correlated with clinical characteristics as well as biopsy and radical prostatectomy findings. Results: Prostate cancers were detected in 230 biopsy sites from 91 patients. The mean peak intensity value of prostate cancer was significantly higher than that of the benign lesions (9.82 +/- 3.73 vs 7.51 +/- 2.97; p<0.001), and the peak intensity value of the cancer foci varied across the prostate. The mixed model analysis revealed that the location and Gleason score of tumour foci were the influencing factors of the peak intensity value, and the former had a stronger influence upon peak intensity than the latter (p=0.000 and 0.040, respectively). However, age, prostate volume or serum prostate-specific antigen of the patient had no significant influence on the peak intensity value (p>0.05). Furthermore, the peak intensity value of tumours larger than 5 mm diameter was significantly higher than tumours of 5 mm or smaller diameter (9.28 +/- 2.46 vs 6.69 +/- 2.65; p<0.001). Conclusions: The prostate cancer lesions with a higher Gleason score and larger tumour size which were located in the lateral peripheral zone (PZ) were more likely to show a marked enhancement. Lesions with lower peak intensity that are located in the medial PZ should also be treated as suspicious.