The agent, gallium-68 (Ga-68), targets gastrin-releasing peptide receptors and integrin αvβ3. When both receptor types are expressed, this allows for tumor contrasting to occur, increasing the number of effective receptors and improving binding affinity.
“Compounds capable of targeting more than one biomarker have the ability of binding to both early and metastatic stages of prostate cancer, creating the possibility for a more prompt and accurate diagnostic profile for both primary and the metastatic tumors,” said Xiaoyuan Chen, lead author on the study and senior investigator at the Laboratory of Molecular Imaging and Nanomedicine at the U.S. National Institute of Biomedical Imaging and Bioengineering in Bethesda, Maryland.
X-rays, CT scans and MRIs are typically used to detect the spread of cancer cells. It is usually hard to determine where it has spread with traditional methods, but the PET radiotracer agent makes it more visible in bones and tissue.
As of 2017, prostate cancer affects 1 in 7 men and usually develops in older men. There are approximately 161,360 new cases per year in the U.S. and 26,730 prostate cancer–related deaths per year, according to the American Cancer Society.
“Although treatable at the early stage, prostate cancer is prone to metastasis,” Chen said. “An effective and specific imaging method of detecting both primary and metastatic lesions is thus of critical importance to manage patients with prostate cancer.”
Prostate cancer occurs when cells in the prostate gland begin to grow uncontrollably. Almost all prostate cancers are considered adenocarcinoma but can include sarcomas, small cell carcinomas, neuroendocrine tumors and transitional cell carcinomas.
In this study, 13 patients with prostate cancer and 5 healthy volunteers were exposed to the Ga-68 agent. It was able to detect 20 bone lesions in 7 prostate cancer patients. However, those patients did not have an elevated prostate-specific antigen level.
“This result is better than bone scanning with MDP,” Chen said. “MDP bone scans are sensitive but lack specificity because localized skeletal accumulation of Tc-99m-MDP can also be observed in the case of trauma and infection.”
The research was published in the Journal of Nuclear Medicine.
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