BERKELEY, CA (UroToday.com) - Avascular areas on contrast-enhanced magnetic resonance imaging (MRI) have been considered to be areas of localized prostate cancer successfully treated by high intensity focused ultrasound (HIFU). However, the optimal timing of MRI has not been discussed. The thermal effect of HIFU is degraded by regional prostatic blood flow. Conversely, the mechanical effect of HIFU (cavitation) is not affected by blood flow and can induce vessel damage.
In this series, the longitudinal change of blood flow on contrast-enhanced MRI was observed from postoperative day 1 (POD1) to POD14 in 10 patients treated with HIFU. The median rates of increase in the non-enhanced volume of the whole gland, transition zone, and peripheral zone from POD1 to POD14 were 36%, 39%, and 34%, respectively. In another pathological analysis of the prostate tissue of 17 patients, immediately after HIFU and without neoadjuvant hormonal therapy, we observed diffuse coagulative degeneration and partial non-coagulative prostate tissue around arteries with vascular endothelial cell detachment. These results support a time-dependent change of the blood flow in the prostate treated with HIFU as observed on contrast-enhanced MRI. Additionally, the pathological findings in our study supported the longitudinal changes of the MRI findings.
The precise feedback of actual effectiveness will contribute to the evaluation of effectiveness of whole-gland therapy and focal therapy with HIFU and the technical improvement for surgeon for successful treatment. We anticipate that further large-scale studies will investigate the most appropriate timing of contrast-enhanced MRI for evaluation of the effectiveness of HIFU for localized prostate cancer.
Sunao Shoji, MD, PhD as part of Beyond the Abstract on UroToday.com. This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.
Department of Urology, Tokai University Hachioji Hospital, 1838 Ishikawa-machi, Hachioji-shi, Tokyo 192-0032 Japan