NIH grant to evaluate PET's potential to stage prostate cancer

Thomas Jefferson University Hospital, Philadelphia

Jefferson's Kimmel Cancer Center and the department of radiology at Thomas Jefferson University in Philadelphia received a five-year, $2.6 million grant from the National Institutes of Health (NIH) to investigate a method that may stage prostate cancers and detect recurrent disease, potentially reducing the number of confirmation biopsies. The technique involves the use of a PET scan and a novel imaging agent.

The study is being led by Mathew L. Thakur, PhD, professor of radiology at Jefferson Medical College of Thomas Jefferson University and the director of the laboratories of radiopharmaceutical research and molecular imaging.

Prostate-specific antigen (PSA) measurements, ultrasound and MRI remain standard tools for diagnosis and management of prostate cancer; however, each requires a biopsy for histologic confirmation. Because biopsies can be invasive, costly and often lead to false-positive results, according to the researchers, there is a need for noninvasive methods that can stage prostate cancer, detect recurrent disease and image metastatic lesions with improved reliability.

Thakur and colleagues are studying Cu-64 peptide biomolecules to evaluate prostate cancer tumors via PET imaging. These agents detect prostate cancer by finding a biomarker called VPAC1, which is overexpressed as the tumor develops.

"The challenge has been to develop an imaging agent that will target a specific, fingerprint biomarker that visualizes prostate cancer early and reliably," Thakur said in a statement.

Previous studies with Cu-64 peptides from Thakur yielded promising results in stratifying breast cancer. A preclinical study published in the Journal of Nuclear Medicine in late 2009 found that 64Cu-TP3805 detected tumors overexpressing the VPAC1 oncogene more accurately in mice than 18F-FDG, a commonly used agent for imaging tumors.

With this NIH grant, researchers will test the hypothesis in both mice and humans, seeking to evaluate two Cu-64 peptides specific for VPAC1 in mice and perform a feasibility study in 25 pre-operative prostate cancer patients, and using the best-suited Cu-64 peptide determined from the mouse studies.

"This noninvasive method could significantly contribute to the management of prostate cancer," said Thakur. "It would result in a reduction of unnecessary biopsy procedures and under treatment or over treatment that yields minimal benefits, incontinence, or impotence."