Researchers at the University of Michigan Comprehensive Cancer Center are working on an imaging technique that is able to measure the progress of treatments for prostate cancer that has spread into nearby bones. The process measures the diffusion of water contained in tumors. The full study appears in the April 15 issue of Cancer Research.

"Currently, we have no way of detecting bone tumor response to therapy, even with all of the imaging options we have available. The magnitude of this problem is huge – as many as 500,000 people in the United States have metastatic breast or prostate cancer to the bone," said Brian D. Ross, PhD, study author and professor of radiology and biological chemistry at the U-M Medical School and co-director of the Molecular Imaging Program at the U-M Comprehensive Cancer Center.

Functional diffusion map, the imaging method used, takes MRI scans and special software to track the diffusion of water through the cells, with changes tracked during the course of treatment. This is because tumor cells slow the movement of water and as they die the movement of water increases.

Researchers studied metastatic prostate cancer in mice; half the mice were given chemotherapy to treat the cancer, while the remaining mice served as an untreated control group. The mice that did not receive treatments had little or no clear change in water diffusion. At the end of the study, the researchers removed the tumors and found the functional diffusion map predicted the tumors’ response to treatment.

"The functional diffusion map could serve as an early biomarker indicating that a tumor is responding to treatment. This could allow patients to switch to an alternative therapy without wasting time on a treatment that is not working," said another study author Kenneth Pienta, MD, professor of internal medicine and urology and director of the Urologic Oncology Program at the U-M Comprehensive Cancer Center.