Extended prostate biopsy predicts improved progression-free survival
MedWire News: US study results indicate that prostate biopsy protocols involving a greater number of cores are significantly associated with improved biochemical progression-free survival (bPFS) compared with protocols that remove fewer cores.
The research team believes their finding supports comprehensive regional sampling of the prostate to enhance diagnostic accuracy.
"With the diagnostic accuracy that is inherent to extended biopsy, treatment can be selectively intensified in the subset of patients with high-risk disease, resulting in better biochemical outcome," say Gregory Merrick from Wheeling Hospital in West Virginia, and colleagues.
They explain that a significant proportion of prostate cancer patients may not receive appropriate therapy because of under-diagnosis of Gleason score at prostate biopsy, adding that a reliable Gleason score evaluation depends on adequate sampling at biopsy.
The team therefore examined whether rates of bPFS, cause-specific survival (CSS), and overall survival (OS) were related to biopsy core number in a cohort of 1613 prostate cancer patients treated with permanent brachytherapy.
The overall 10-year bPFS, CSS, and OS rates were 95.6%, 98.3%, and 78.6%, respectively.
Patients were divided according to biopsy core number: more than 20 (n=38), 13-20 (n=81), 10-12 (436), 7-9 (434), and 6 or less cores (n=624), and the respective 10-year bPFS rates in these categories were 100%, 100%, 98.3%, 95.8%, and 93.0%. These rates were not dramatically different after adjustment for hormone therapy use - a potential confounder of bPFS.
Cox regression analysis showed that the number of biopsy cores and the patients' risk group were significantly predictive of bPFS.
Like bPFS, 10-year CSS and OS rates were higher for men who received extended (more-cores) biopsy protocols. Respective rates were 100% and 100% for more than 20 cores, 100% and 93.4% for 13-20 cores, 98.6% and 85.0% for 10-12 cores, 99.7% and 79.2% for 7-9 cores, and 97.3% and 76.1% for less than 6 cores.
However, on multivariate analysis, number of biopsy cores was not predictive of CSS or OS. Instead, Gleason score and risk group, and age, diabetes status, and tobacco use were predictive of CSS and OS, respectively.
"This study demonstrates a statistically significant improvement in bPFS with higher biopsy core number," conclude the researchers in the International Journal of Radiation Oncology Biology Physics.
"This information is particularly relevant to the brachytherapist as he/she plans the extent of extraprostatic implant coverage and decides whether supplemental therapies may be warranted," they remark.
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By Sarah Guy