Precision Medicine: A New Approach to Diagnosing Prostate Cancer

According to the American Cancer Society, approximately one out of eight men will be diagnosed with prostate cancer at some point in their life. Prostate cancer also is the second leading cause of cancer death in American men. Early detection and treatment are key factors that influence outcomes. However, identifying specific areas where prostate cancer has spread through metastasis often is difficult. To improve patient outcomes, a nuclear medicine physician and a career scientist at Harry S. Truman Memorial Veterans’ Hospital have teamed up to bring leading-edge, bench-to-bedside care to mid-Missouri Veterans.

“When a normal cell in the prostate gland becomes cancerous, the membrane of the cell begins to make too many copies of a protein called prostate-specific membrane antigen, or PSMA,” said Thomas Dresser, MD, PhD, Chief of Nuclear Medicine at Truman VA. “This unique cell marker can help us diagnose prostate cancer. However, current imaging does not clearly identify if and where metastasis has occurred. The key to diagnostic precision is the use of an injectable radiopharmaceutical peptide designed for a specific cancer and used in conjunction with PET (positron emission tomography) imaging.”

Once administered intravenously, radiopharmaceutical peptides are attracted to and bind to cancerous cells. When used in conjunction with PET imaging, these radioactive peptides “light up” on the scan to identify even the smallest amount of disease in its initial growth.

 
 

“Although using cancer-specific radiopharmaceuticals and PET imaging provides clinicians with an outstanding diagnostic tool, in practice, its use is extremely limited,” Dresser said. “Very few facilities have a dedicated and certified radiopharmacy to formulate a specific peptide. Additionally, once mixed, these radiopharmaceuticals have an extremely short shelf life that can be as short as one hour. Therefore, they can only be transported short distances. Handling and formulating radiopharmaceuticals is not only heavily regulated, but their effectiveness also begins to immediately and steadily decline. On-site preparation really is key to their successful use.”

To overcome these obstacles, Timothy Hoffman, PhD, a Research Career Scientist at Truman VA and Professor of Medicine at the University of Missouri School of Medicine, worked with his research team to develop an in-house radiopharmacy at Truman VA for on-site preparation of the peptide-based radiopharmaceutical Ga 68 PSMA-11.

 
 

“Our efforts to create a radiopharmacy for the development of cancer-directed drugs here at Truman VA have been very successful through a multi-institutional effort with support from the MU Department of Medicine,” Hoffman said. “As a result, three months ago, Truman VA became the first VA hospital in the U.S. to offer this level of care in-house. Since then, we have participated in an FDA-approved phase III clinical trial where more than two dozen Veteran patients have benefited directly from this leading-edge care.”

On Dec. 1, 2020, the U.S. Food and Drug Administration (FDA) granted approval of Ga 68 PSMA-11 to be produced at the University of California, Los Angeles, and the University of California, San Francisco. It’s use, in conjunction with PET imaging, to precisely diagnose the spread of prostate cancer is expected to also be approved nationwide within the next several months. Until that occurs, all Veterans who receive care at Truman VA have the option to participate in the ongoing FDA approved phase III clinical trial, affording them access to the highest level of diagnostic care without the need to travel great distances.

“My dad served as a U.S. Army Air Force pilot in the European Theater during World War II,” Hoffman said. “Several of my uncles served in U.S. Army and U.S. Marine Corps infantry units in both the European and Pacific Theaters. Having grown up around these great men, I developed a high level of respect for Veterans. I know I also speak for Dr. Dresser, who is a retired U.S. Navy captain, when I say that we want the best for our nation’s heroes.”