29 Jan Targeted MR/Ultrasound Biopsy May Improve Prostate Cancer Diagnosis
Medical Research: What is the background for this study? What are the main findings?
Response: For men suspected of having prostate cancer due to an elevated PSA or abnormal digital rectal exam, the next step in their diagnostic workup has traditionally been a standard 12-core biopsy to evenly sample the entire gland. Unlike most other cancers, prostate cancer is one of the few solid tumors left which is diagnosed by randomly sampling the gland with the hope of biopsying the tumor, if it is present. This paradigm has been largely due to the fact that imaging to date has been limited in its ability to identify prostate cancer. Recent advancements in multiparametric MRI of the prostate however has significantly improved clinician’s ability to identify regions in the prostate suspicious for cancer. This has led to the emergence of MR/Ultrasound fusion technology which allows for targeted biopsy of the prostate into regions suspicious for cancer.
Although conceptually, it makes sense that a targeted biopsy has the potential to perform better than the standard random sampling of the prostate in the diagnosis of prostate cancer, studies were needed to understand if this is true, and if so, if the improvement was substantial enough to justify the extra expense and effort needed to obtain a MRI guided biopsy. This study performed at the National Cancer Institute’s Clinical Center sought to address this clinical question of interest. From 2007-2014, a total of 1003 men suspected to have prostate cancer underwent an MRI of the prostate. If an area of suspicion was seen in the prostate, these men underwent both the targeted biopsy of the suspicious region in the prostate as well as the standard 12-core needle biopsy during the same session. The results from the targeted biopsy were compared to the results of the standard biopsy.
The key findings in this study was that targeted biopsy improved the rate at which high-risk clinically significant cancer was diagnosed by 30%. Of interest, the study also found that low-risk, clinically insignificant disease (the type of prostate cancer that is unlikely to cause any harm to the patient over the course of his natural life) was decreased in diagnosis by 17%. Decrease of diagnosis of such disease has the potential benefit that it could lead to less over-treatment of cancer that never needed to be treated. In a subset of 170 men that ultimately underwent surgery to remove the prostate to treat their cancer, we were further able to examine how well the prostate biopsy reflected the actual cancer burden in the whole gland. It is well known that standard biopsy can actually underestimate the total cancer grade in the whole prostate in upwards of 30-40% of cases. We found that the targeted biopsy was significantly better at predicting whether the patient had intermediate to high-risk cancer compared to standard biopsy. Through further analysis using a statistical method called decision curve analysis, we further found that for men who wish to undergo surgery for intermediate to high-risk cancer, but wish to go on active surveillance for low-risk cancer, targeted biopsy led to better decision making compared to standard biopsy, or even the two techniques combined.
Medical Research: What should clinicians and patients take away from your report?
Response: Targeted MR/Ultrasound fusion biopsy is a promising technology to improve the diagnosis of prostate cancer. While further study is needed to understand if fusion biopsy should be integrated into standard screening, it is reasonable to utilize this technology in cases where the standard approach has failed to diagnose the prostate cancer despite multiple biopsy attempts, and in men who are planning to go on active surveillance and would be interested in a more reliable confirmation biopsy.
Medical Research: What recommendations do you have for future research as a result of this study?
Response: While this study demonstrated improvement in the accuracy of diagnosing the risk of the prostate cancer, it is unclear if this improvement will translate into long-term improvements in clinical endpoints such as cancer survival. Future studies are needed to study if the benefits noted in this study translate to long-term clinical endpoints of importance.
Comparison of MR/Ultrasound Fusion-Guided Biopsy With Ultrasound-Guided Biopsy for the Diagnosis of Prostate Cancer.
JAMA 2015 Jan;313(4):390-397
M Minhaj Siddiqui, Soroush Rais-Bahrami, Baris Turkbey, Arvin K George, Jason Rothwax, Nabeel Shakir, Chinonyerem Okoro, Dima Raskolnikov, Howard L Parnes, W Marston Linehan, Maria J Merino, Richard M Simon, Peter L Choyke, Bradford J Wood, Peter A Pinto
MedicalResearch.com Interview with:, & Mohummad Minhaj Siddiqui, MD and Peter A. Pinto, M.D (2015). Targeted MR/Ultrasound Biopsy May Improve Prostate Cancer Diagnosis MedicalResearch.com