They hypothesized that the number of prostate biopsy cores should vary based upon the size of the prostate in order to always sample the same volume per core.
The database was comprised of 3,040 patients who underwent prostate biopsies between 1994 and 2008 at a single VA Medical Center. The prostate volume/number of cores was derived and comparative analysis performed to determine the CaP detection rates. Of the 2,224 biopsies included in the analysis, 684 (31%) had CaP. The median prostate volumes for the positive and negative biopsy groups were 33cc and 43cc, respectively. Both groups had a median of 12 biopsy cores performed. The median PSA was 8.4ng/ml for those with a negative biopsy compared to 6.2ng/ml for those with a positive biopsy.
The distribution of positive biopsies by the TRUS size/number of cores from 0-3.0, 3.01-6.0, 6.01-9.0, and >9.01g/core, were 39.5, 43.5, 12.7, and 4.2%, respectively. The distributions of negative biopsies based on the same ratios were 24.3, 42.4, 19.8, and 13.6% of the biopsies per ratio group. Comparing positive with negative biopsy ratios revealed that only a ratio of 3.0-6.0 had statistical significance. The median TRUS/core volume ratios were 3.5cc/core for those with CaP and 4.7for those with negative biopsies. In multivariable analysis including age, race, prostate volume, DRE and PSA level, TRUS size/core volume had a significant impact on CaP detection with a relative risk ration of 1.29.
Sfakianos JP, Thorner DA, Dovirak O, Weiss JP, Karanikolas NT
BJU Int. 2011 May 31. Epub ahead of print.
10.1111/j.1464-410X.2011.10239.x
PubMed Abstract
PMID: 21627750
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