Contrast-enhanced transrectal color doppler ultrasonography (TRCDUS) for assessment of angiogenesis in prostate cancer.

BACKGROUND

The clinical relevance of tumor angiogenesis has been investigated in several human tumors, including prostate carcinoma (PC). Previously, we found angiogenesis, measured as microvessel density (MVD), to be an independent prognostic factor in PC. Therefore, we evaluated contrast-enhanced Transrectal Color Doppler Ultrasonography (TRCDUS) for assessment of angiogenesis in PC.

MATERIALS AND METHODS

We investigated 15 patients with PC before radical prostatectomy (RP) and 3 control patients before radical cystoprostatectomy. TRCDUS was performed using a micro-bubble-based ultrasound enhancer Levovist for identifying hypervascularized areas within the prostate. Computer-assisted quantification of color pixel intensity (PI) was used to evaluate objectively the hypervascularized areas; resistive index (RI) measurements were also obtained in these areas. After histopathological examination of the entire prostate gland for tumor confirmation, immunohistochemical evaluation of MVD using a polyclonal antibody against factor VIII was performed as described by Weidner et al. (N Engl J Med 324: 1-8, 1991). TRCDUS findings were correlated with the immunohistochemical data.

RESULTS

All patients showed hypervascularized areas (range: 1-9) on contrast-enhanced TRCDUS. Hypervascularized areas showed a sensitivity of 50.8% and a specificity of 95.2% for detecting PC. Analysis of TRCDUS data and immunohistochemistry revealed a significant correlation between PI and MVD in PC specimens, demonstrating a correlation coefficient of r2 = 0.977 (p<0.001). RI did not correlate with MVD.

CONCLUSION

Contrast-enhanced TRCDUS showed a high specificity in identifying PC. PI correlated significantly with MVD. Therefore, quantification of color Doppler signals seems to be helpful for assessment of angiogenesis in PC.