In the latest issue of the Journal of Nuclear Medicine, researchers have confirmed that a new PET radio tracer for diagnosing primary and metastatic prostate cancer is safe and effective.

The gallium-68-labeled peptide BBN-RGD agent targets both gastrin-releasing peptide receptor and integrin αvβ3. Unlike single-receptor targeting, dual-receptor targeting allows for tumor contrast when either or both receptor types are expressed.

"This approach is better than targeting a single receptor," Dr. Xiaoyuan Chen, senior investigator of the study, told HCB News. "In other words, the sensitivity of detection is improved [over] other radiotracers."
The study involved 13 patients with prostate cancer. Four were newly diagnosed, nine received therapy, and five were healthy volunteers.

They found that Ga-68-BBN-RGD PET/CT was able to detect 20 bone lesions in seven patients with primary prostate cancer or after radical prostatectomy. The patients with bone metastases didn't necessarily have elevated prostate specific antigen level.

Since no adverse events were reported during the procedure and at the two-week follow-up, Ga-68-BBN-RGD was deemed safe.

Chen noted that this is a better result than bone scanning with the most common radio tracer used today, technetium-99m-MDP. MDP bone scans are sensitive, but lack specificity because localized skeletal accumulation of Tc-99m-MDP can also be observed in trauma and infection cases.

"It may become the standard for diagnosing prostate cancer," said Chen. "Another major application of this would be using the same peptide construct to label therapeutic isotopes or cytotoxic agents for targeted treatment of prostate cancer."

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