Contrast-enhanced ultrasonography detects high-grade prostate cancer better than conventional methods, and so it is a more appropriate approach for screening clinically important cancers and monitoring low-risk ones with fewer biopsies. This phase III study was conducted by researchers from Thomas Jefferson University and Hospitals.
Although ultrasonography of the prostate is commonly used to assess the size of the gland and to place the needle during systemic biopsy, it is limited by difficulty in distinguishing benign from malignant tissue. Contrast-enhanced ultrasonography uses microbubble contrast agents, which are tiny bubbles of gas in a supporting shell that are injected into the patient to better measure changes in blood flow. Like many cancers, prostate cancer has abnormal blood vessel flow, and that change in flow in the prostate can be measured by ultrasonography. The microbubbles enhance the reflection of the ultrasound waves.
This randomized, double-blind trial of 311 men, 118 of whom had positive prostate cancer biopsies, used both contrast-enhanced ultrasonography and a systemic 12-core biopsy protocol on all patients. The mean age of the patients was 62 years, and their mean PSA level was 6.5 ng/mL. Targeted biopsies using contrast-enhanced ultrasonography with microbubbles detected significantly more prostate cancer that was higher volume or higher grade (55%) compared with a conventional prostate biopsy technique (17%).
Though the technique has been used successfully in Europe for some time, the US Food and Drug Administration has not approved it for use for prostate screening. It is used for other imaging applications, and the researchers at Jefferson say it is ready for primetime in the United States.
“Today, a physician may sample 12 to 18 tissue cores from the prostate in order to help diagnose a patient. But with contrast-enhanced, that number drops to six or even less,” says lead author Ethan Halpern, MD, co-director of the Prostate Diagnostic Center at Thomas Jefferson University Hospital and professor of Radiology and Urology at Thomas Jefferson University. “So it’s less invasive, and a more effective guidance tool. We’ve found that with contrast-enhanced ultrasound, we are much more likely to detect cancers on the image, and in this case, the higher grades.”
“Our ultimate goal is to perform a limited number of targeted biopsies and leave the rest of the prostate alone,” says Halpern. “This will provide a safer, more cost-effective approach to diagnosing prostate cancer.” This study was published in Journal of Urology.