ORLANDO, FL USA (UroToday.com) - Tumor volume is an important prognostic factor for men with prostate cancer, yet it has proven difficult to measure pre-operatively. Random biopsy core length and percentage of core involvement have both been used as proxies, but these measures suffer from poor accuracy. Okoro et al. from the National Cancer Institute now report that targeted, image-guided biopsy can provide a significantly better measure of prostate cancer tumor volume.
The authors randomly selected 100 patients who had undergone multiparametric prostate MRI (MP-MRI) followed by MRI/US fusion-guided biopsy, as well as extended sextant 12-core biopsy. Radiologic tumor volume was determined by manually sectioning each tumor using iCAD software, given that this has been shown to correlate well with volume noted on whole mount pathology at radical prostatectomy. Tumor burden on targeted and random biopsy cores was then compared to tumor volume measured on MRI. Targeted biopsy tumor burden correlated well with estimated tumor volume, while random biopsy percent core involvement and absolute mm of cancer did not. Targeted biopsy also detected clinically significant (> 500 mm3) tumors with a 70% accuracy, as compared to 44% for random biopsy.
The authors conclude that targeted biopsy tumor burden provides an accurate, practical pre-operative measure of prostate cancer tumor burden. Such knowledge may present an important improvement in the risk stratification of men with prostate cancer, especially in those men in which such metrics are an essential component to treatment planning such as active surveillance and potentially focal therapy.
Presented by Chionyerem Okoro, MD at the American Urological Association (AUA) Annual Meeting - May 16 - 21, 2014 - Orlando, Florida USA
National Cancer Institute (NCI), Bethesda, MD USA
Written by Dima Raskolnikov, National Cancer Institute (NCI)