Researchers at University of California at San Francisco (UCSF) and GE Healthcare have developed a new technology that appears to rapidly assess the presence and aggressiveness of prostate tumors in real time, by imaging the tumor’s metabolism.
Data on the first four patients the procedure was tried on was presented on December 2 at the Radiology Society of North America’s annual conference.
The results being presented validate extensive preclinical research that has linked the speed at which tumors metabolize nutrients to their aggressiveness and growth. This imaging technique also has been used to show early biochemical changes in animal tumors in real time as they respond to medication therapy, long before a physical change occurs. This represents a revolutionary approach to assessing the precise outlines of a tumor, its response to treatment and how quickly it is growing.
According to the researchers, this technology has produced the same response in human patients’ tumors as it did in laboratory studies, even at the lowest dose, according to Sarah Nelson, PhD, a professor of Radiology and Biomedical Imaging and a member of the California Institute for Quantitative Biosciences (QB3) at UCSF.
“This is a key milestone that could dramatically change clinical treatment for prostate cancer and many other tumors,” Nelson said. “We had shown this worked in animal models and tissues samples. Now, in men, we are seeing exactly the type of results we had hoped for.” Nelson also said, “If we can see whether a therapy is effective in real time, we may be able to make early changes in that treatment that could have a very real impact on a patient’s outcome and quality of life,”
If this technology holds up to additional testing we will find that a clinician will be able to get immediate feedback on whether a cancer is aggressive and if therapy is working, either during standard treatment or in a clinical trial. This would provide a tremendous advantage in deciding what treatment protocols work and when it might be necessary to change protocols. However, the results are limited to disease progression and do not have an ability to predict survival time.
This new technology uses compounds involved in normal tissue function – in this case, pyruvate, which is a naturally occurring by-product of glucose and lactate, also known as lactic acid. The pyruvate needs to be prepared in a strong magnetic field at a temperature of minus 272° C, then rapidly warmed to body temperature and transferred to the patient in an MRI scanner before the polarization decays back to its native state. Then, newly developed equipment is used to increase the visibility of those compounds by a factor of 50,000 in a magnetic resonance imaging (MRI) scanner.
The researchers have found that they then are able to get a highly defined and clear image of the tumor’s outline, as well as a graph of the amount of pyruvate in the tumor and the rate at which the tumor converts the pyruvate into lactate.
The trial results presented at the conference only involved men with prostate cancer who were doing active surveillance. However, if the technology proves itself after additional trials, its importance for men with advanced prostate cancer is clearly evident, but will also need to be verified.
Joel T Nowak, M.A., M.S.W.