Fusion biopsy boosts cancer detection in enlarged prostates
medwireNews: Researchers have shown that using magnetic resonance (MR) imaging to guide transrectal ultrasound (TRUS) prostate biopsy can increase cancer detection in men with enlarged prostates.
In a cohort of men with a high mean prostate volume, Peter Pinto (National Cancer Institute, Bethesda, Maryland, USA) and colleagues found that the MR-US approach picked up cancers in a significant proportion of those who had negative biopsies under TRUS. Furthermore, detection of high-risk prostate cancers did not decline according to prostate volume under MR-US.
"These findings emphasize the value of the fusion technology to detect and risk-stratify cancer on high resolution imaging and accurately target visualized lesions for biopsy," they comment in the Journal of Urology.
The study included 649 patients with a mean whole prostate volume of 58.7 cc who underwent MR-US fusion biopsy during 2009 to 2012. TRUS-guided biopsy had detected cancer in 41.9% of the men.
Of 528 patients who had undergone at least one previous TRUS, a higher proportion of men with glands of a volume greater than 40 cc (n=379) had a prior negative biopsy than men with smaller glands, at 63.1% versus 45.6%.
Of the 307 men who had a prior negative TRUS biopsy, 128 (42%) were identified as having prostate cancer by MR-US fusion.
However, this detection rate varied inversely according to prostate volume, such that it was 69.1% in those with a volume of less than 40 cc but only 26.5% in those with a volume of 115 cc or more. The authors found the same correlation when they looked at patients with no prior diagnosis, regardless of whether they had undergone a prior biopsy, and the entire cohort.
Notably, the percentage of patients diagnosed with high-risk (Gleason score ≥8) prostate cancer was similar across prostate sizes, indicating that the fusion technology can detect high Gleason score tumors even in enlarged prostates.
It is well established that men with enlarged prostates have a lower prostate cancer detection rate on TRUS biopsy, Pinto and colleagues explain. However, the proposed alternative approach for such men - gantry multiparametric MR imaging - is impractical, costly, and inconvenient for the patient, they say, while conversely, MR-US can be undertaken in the urologist's office.
They conclude that MR-US "represents a promising solution for those patients with a clinical suspicion of [prostate cancer] complicated by enlarged prostates secondary to [benign prostatic hyperplasia] changes."
medwireNews (www.medwirenews.com) is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2013
By Kirsty Oswald, medwireNews Reporter