UCSF investigators have shown that adding an emerging metabolic imaging technique to MR–transrectal ultrasound fusion prostate biopsies makes it possible to detect the extent and aggressiveness of prostate cancer more accurately than ever. This information helps to inform treatment decisions and ultimately improve patient outcomes.
Hyperpolarized (HP) carbon-13 (13C) pyruvate MRI provides real-time assessment of the glycolytic metabolism rate of prostate cancer cells, which was previously inaccessible to imaging. The research team’s recent study demonstrates the safety and feasibility of integrating HP 13C MR biomarkers into the multiparametric MRI workflow.
“HP 13C MRI is a five-minute, nonradioactive add-on to standard imaging procedures that can help to identify aggressive lesions in the prostate,” said coauthor Robert Bok, MD, PhD, professor at the UCSF Hyperpolarized MRI Technology Resource Center (HMTRC) and in the Department of Radiology and Biomedical Imaging. “The advantage is being able to detect these lesions earlier in patients, including those on active surveillance.”
“This technique provides much more dynamic and metabolic information about prostate cancer than we can get with standard MRI,” said coauthor Matthew Cooperberg, MD, MPH, urologic cancer surgeon and co-director of the Prostate Cancer Program at the UCSF Helen Diller Family Comprehensive Cancer Center.
Tracking metabolic changes in real time
The technique uses a specific imaging marker to track the metabolic changes that occur in the development of prostate cancer.
“The patient receives an injection of pyruvate – a molecule that’s part of normal aerobic metabolism – labeled with one atom of carbon-13,” Cooperberg said. “You can then follow the carbon atom in order to track, in seconds, what happens to that pyruvate. One of the hallmarks of cancer is a switch from aerobic to anaerobic metabolism. So the ratio of pyruvate to lactate is an indicator of the aggressiveness of cancer.”
“This method improves the detection of aggressive disease,” said coauthor John Kurhanewicz, PhD, professor at the HMTRC and in the UCSF departments of radiology and biomedical imaging, urology and pharmaceutical chemistry. “We’ve never before had the ability to accurately assess this.”
Groundbreaking research at UCSF
The recent study builds on the team’s earlier work. In 2013, UCSF investigators conducted the first in-human study of HP 13C pyruvate MRI to noninvasively characterize alterations in tumor metabolism in patients with prostate cancer. They observed metabolic changes in regions of biopsy-proven cancer and were able to detect cancer in prostate regions previously thought to be tumor-free based on conventional anatomic imaging.
The researchers are conducting ongoing HP 13C pyruvate MRI studies focused on the safety, feasibility and efficacy of this imaging method to improve disease diagnosis, accelerate treatment assessment and monitor response to therapy.
“The focus of the HMTRC is to advance the technical development of hyperpolarized imaging techniques and disseminate them,” Kurhanewicz said. “We continue to push the envelope beyond 13C pyruvate to develop new probes and their translation to the clinic. Our investigators are involved in hyperpolarized carbon imaging for many diseases, including brain cancer, kidney cancer, liver disease and other metabolic diseases.”
“The HMTRC helps build collaborations as part of its function,” Bok said. “We've always had a close working relationship with the cancer center and the urology department. UCSF has been one of the leaders in HP 13C MRI development, from its early inception. Although it’s only in use at a few centers nationally now, our hope is it will be distributable more broadly in the future.”
Cancer research and treatment take place within the UCSF Helen Diller Family Comprehensive Cancer Center.
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