According to a recent article published in The Journal of Urology, the use of contrast enhanced color Doppler in endorectal ultrasound improves the detection of prostate cancer.
Prostate cancer is a common cancer among men in the United States. Prostate cancer is the second leading cause of cancer death in men in the United States. The prostate is a walnut-size gland that is located between the bladder and rectum and forms a component of semen. Prostate specific antigen (PSA) levels (a protein produced by the prostate that is elevated when cancer is present), a digital rectal exam (DRE) and transrectal ultrasound are common tests used to detect prostate cancer. If any suspicious mass is found through these tests, a patient must then undergo biopsies (the removal of a sample of tissue) to definitively determine whether cancer exists. However, it is imperative that a physician takes a biopsy from the area in the prostate where the cancer exists to provide accurate diagnostic information. Physicians often use endorectal ultrasound to help determine where in the prostate to take a biopsy. Researchers are attempting to improve upon the accuracy of ultrasound in the guidance of placement of biopsies, including the introduction of contrast, which help physicians to discern between healthy looking tissue and possible sites of cancer.
A new development in ultrasound involves the use of color Doppler imaging with microbubble contrast so that physicians are better able to determine the presence and exact location of a mass within the prostate. Doppler imaging can sense differences in velocity (i.e. blood flow versus solid tissue) and transmits these differences through different color pixels to create a picture on a screen. Microbubbles are tiny bubbles of gas that can permeate through small blood vessels without creating any harm. The microbubbles further enhance imaging by increasing the intensity of backscatter signal. Since blood vessels and blood flow are more prevalent in cancerous tissues than regular tissues, microbubbles tend to concentrate in the cancer, which is revealed on the created picture. This allows physicians to more accurately locate where biopsies should be taken.
Researcher from France recently conducted a clinical study to determine the effectiveness of contrast-enhanced color Doppler ultrasound using microbubbles in determining biopsy sites in men suspected of having prostate cancer. This trial included 85 men who underwent conventional Doppler and microbubble-enhanced color Doppler during the biopsy procedure. The results between the two were directly compared based on biopsy results. Contrast-enhanced color Doppler had a 93% detection rate of prostate cancer, compared with only 54% for un-enhanced color Doppler. Biopsies from areas of the prostate that did not contain cancer occurred in 21% of biopsies under Doppler that was not enhanced, compared with only 11% of biopsies under contrast-enhanced Doppler.
The researchers concluded that microbubble-enhanced color Doppler used for endorectal ultrasound improves the detection of prostate cancer and reduces unnecessary biopsies, compared to color Doppler that is not enhanced. They also state that this procedure is simple and not time consuming. Patients suspected of having prostate cancer may wish to speak with their physician about the risks and benefits of microbubble-enhanced color Doppler in endorectal ultrasound for biopsy placement or the participation in a clinical trial evaluating other novel screening approaches. Two sources of information regarding ongoing clinical trials include the National Cancer Institute (cancer.gov) and www.cancerconsultants.com. Cancerconsultants.com also provides personalized clinical trial searches on behalf of patients.
Reference: Roy C, Buy X, Lang H, et al. Contrast enhances color Doppler endorectal sonography of the prostate: efficiency for detecting peripheral zone tumors and role for biopsy procedure.
The Journal of Urology. 2003;170:69-72.
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