Targeted Fusion Biopsy May Improve PCa Detection
SAN FRANCISCO—Prostate cancer (PCa) detection rates may be markedly improved by adding targeted fusion biopsy to conventional blind random biopsies, according to a new study presented at the 37th Annual Scientific Meeting of the Society of Interventional Radiology.
“From an economic and public health perspective, early diagnosis, more sensitive screening, and more accurate characterization could have huge implications,” said principal investigator Bradford Wood, MD, Director of the Center for Interventional Oncology at the National Institutes of Health (NIH), Bethesda, Md. “Information is power, and this fusion system allows you to get and use the imaging information without needing to tie up an expensive machine during the procedure. This puts a tool in urologists' hands that meets the clinical need, and makes an otherwise ‘blind' biopsy smarter. This multidisciplinary approach allows improved cancer detection and better characterization for those patients who may not need surgery or radiation.”
Prostate biopsy currently is performed blindly without focal imaging guidance other than ultrasound to aim the needle towards the peripheral zone or a specific sextant region of the prostate. This conventional technique is both blind and random, and does not use magnetic resonance imaging (MRI) information that might localize tumors. “Up to now, Physicians are often happy to just be biopsying anywhere in the gland, but they can now target the needles towards the areas suspicious for cancer,” Dr. Wood said.
The multimodality fusion navigation system for prostate biopsy developed by Dr. Wood and his colleagues allows for real-time mapping and referencing to pre-procedural magnetic resonance images. This can be helpful in the ultrasound guidance of the needle towards areas of suspicion, and also can map out areas of prior positive biopsy in select patients undergoing active surveillance.
Dr. Wood's team assessed the clinical utility of the fusion system in a clinical trial that involved 595 prostate biopsies in 520 patients. (Hayet Amalou, MD, also of NIH, presented results from the same group for fusion-guided biopsy and ablation of various types of tumors. The study involved 10,000 tracked needles and 720 procedures.) Patients underwent multi-parametric prostate MRI. The researchers then classified lesions according to suspicion level for cancer: low, moderate, or high. Patients underwent standard 12 sextant biopsies as well fusion-guided ultrasound biopsy of targets defined by pre-procedural MRI.
Adding fusion-targeted prostate biopsy to conventional random biopsy in patients with suspicious targets on MRI yielded marked increase in cancer detection rates. “The detection rate was markedly improved. In fact, the detection rate was almost doubled in certain patients with high-suspicion targets on MRI,” Dr. Wood said. “It is making biopsy smarter. The technology also lets you record the area where you are sampling so you can go back to see that area again in patients with non-aggressive cancer. This more accurate characterization of the tumor could be of tremendous value.”
He said this approach adds clinical value to standard blind prostate biopsies in the setting of previous negative biopsy and anterior, apical, or central gland lesions visible on MRI that might not otherwise be sampled by conventional ultrasound guided biopsy. In this analysis, the suspicion level on MRI correlated with Gleason scores, and prior biopsy location was used to map subsequent biopsy location in patients with low Gleason scores undergoing surveillance biopsy.
“We are trying to define where the technology will fit in the treatment paradigm,” Dr. Wood told Renal & Urology News. If we get a Gleason 6, then that patient may not need treatment or surgery, and may get watchful waiting. However, we don't always know exactly what is going on at a molecular level. With this technique, we have mapped the sample, and we can not only get to the suspicious area the first time, but we can also get back to it at a later date, so we can see if the cancer has changed.”
Other key members of the multidisciplinary prostate team are Peter Pinto, MD, Peter Choyke, MD, and Baris Turkbey, MD.