A new diagnostic technique using color Doppler with an ultrasound contrast agent is more effective than conventional systematic biopsy in diagnosing prostate cancer, conclude the authors of a research letter in this week's issue of The Lancet.
Prostate cancer detection is currently based on three diagnostic tests: serum prostate-specific antigen (PSA), digital rectal examination, and transrectal ultrasonography.
Widespread use of PSA as a screening tool has led to increased numbers of patients who are evaluated with prostate biopsy, but conventional systematic biopsy strategies fail to detect about a third of prostate cancers.
Cancerous tissue generally grows more rapidly than healthy tissue and has increased blood flow compared with healthy tissue. A microbubble ultrasound contrast-agent can be used to improve the detection of tumor vascularity.
Ferdinand Frauscher and colleagues from Thomas Jefferson University, Philadelphia, USA, and from the University Hospital Innsbruck, Austria, compared targeted biopsy of the prostate guided by contrast-agent enhanced transrectal ultrasound with conventional systematic grey-scale ultrasonography-guided biopsy for the detection of prostate cancer.
Each of 84 patients (average age 57 years) was each assessed by two independent investigators; the first investigator performed targeted biopsy of the prostate based upon contrast-agent enhanced color Doppler imaging; the second investigator took biopsy samples of the prostate in a standard geometric distribution, guided by conventional grey-scale ultrasonography.
Prostate cancer was present in 24 (29%) of patients. Cancer was detected in 23 patients assessed by contrast-agent enhanced color Doppler targeted biopsy, compared with 17 patients assessed by conventional grey-scale ultrasonography-guided biopsy.
Furthermore, prostate cancer was detected by contrast-agent enhanced color Doppler in seven (8%) patients with a negative systematic biopsy sample.
Closer comparison of the two diagnostic tests showed that prostate-cancer detection was more than four times more likely with contrast-agent enhanced color Doppler targeted biopsy than with systematic grey-scale ultrasonography-guided biopsy.
Ferdinand Frauscher comments: "Our results suggest that this technique may allow for a limited targeted biopsy approach, which will be cost-effective provided that the cost of the ultrasound contrast-agent ($65 per patient) is less than the savings based upon the reduced number of biopsy cores ($110 per patient).
"These results should be confirmed for different populations in other countries to determine whether a limited, targeted biopsy approach is applicable in other clinical settings."
(Reference: The Lancet, 9th June 2001.)
[Contact: Dr. Ferdinand Frauscher]