NEW YORK (Reuters Health), Oct 16 - An increase in prostate-specific antigen (PSA) level of 1.2 ng/mL over the nadir should be considered a biochemical failure after high-intensity focused ultrasound for prostate cancer, according to authors of a paper in the October issue of BJU International.
"High-intensity focused ultrasound (HIFU) is a minimally invasive therapy for treating localized prostate cancer, consisting of focused ultrasound energy emitted from a transducer, which induces tissue damage by mechanical and thermal effects, and by the ensuing tissue cavitation," Dr. Andreas Blana, of the University of Regensburg, Germany, and colleagues write. "HIFU is becoming increasingly accepted for the treatment of prostate cancer."
To determine the best biochemical predictor of future clinical failure, the researchers analyzed registry data on 285 prostate cancer patients treated with HIFU between 1997 and 2006.
Criteria for clinical failure were a positive prostate biopsy after HIFU, the initiation of secondary prostate cancer treatment, radiographic evidence of prostate cancer metastases, or prostate cancer-related death.
The investigators then compared five biochemical parameters for their sensitivity, specificity, positive predictive value, and negative predictive value as markers of clinical failure risk: PSA threshold values, "PSA nadir plus," PSA velocity, PSA doubling time, and the American Society for Radiation Therapy and Phoenix definition of biochemical failure.
At a median follow-up of 4.7 years, the median PSA was 0.76. The cohort's median PSA nadir was 0.13 ng/mL, which occurred at a median of 12.9 weeks after HIFU treatment.
Overall, 71 patients (25%) experienced clinical failure.
"The biochemical events that best predicted clinical failure in the current study were PSA thresholds of 1.2 to 1.4 ng/mL, a 'PSA nadir plus 1.1 to 1.3 ng/mL,' PSA velocities of at least 0.3 ng/mL per year, and PSA doubling times of 1.25 and 1.75 years," Dr. Blana and colleagues explain.
"The two specific definitions that best predicted clinical failure were 'nadir + 1.2' and a 'PSA velocity >0.2 ng/mL per year.' "
BJU Int 2009;104:1058-1062.
Last Updated: 2009-10-15 16:53:48 -0400 (Reuters Health)
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