A recent blog post discussed a newly approved imaging agent with an unwieldy name: gallium-68 PMA-11. Delivered in small amounts by injection, this minimally radioactive tracer sticks to prostate cancer cells, which subsequently glow and reveal themselves on a positron emission tomography (PET) scan. Offered to men with rising PSA levels after initial prostate cancer treatment (a condition called biochemical recurrence), this sort of imaging can allow doctors to find and treat new tumors that they might otherwise miss. With currently available imaging technology, such tumors could potentially escape detection until they were larger and more dangerous.
But while gallium-68 PMA-11 is the latest PET tracer to win FDA approval, not everyone can get it. In the United States, it’s currently available only to patients treated at the University of California, Los Angeles, or the University of California, San Francisco, where the tracer is manufactured. However, two other PET tracers approved for prostate cancer imaging in the US are becoming more accessible.
In January 2021, a team at Stanford University published findings showing that one those tracers, called fluciclovine F18 (trade name Axumin), identified significantly more metastatic cancers than other conventional types of imaging. Axumin was approved in 2016, and these are among the first data to show how well the tracer performs in real-world settings.
The Stanford researchers reviewed medical records from 165 men who had been given Axumin PET scans between September 2017 and December 2019. All the men had biochemical recurrence, and 70 of them were also imaged with other technologies, including CT scans, bone scans, or MRIs.
Axumin PET scans outperformed all the other tests with respect to tumor detection. In all, 110 men had PET-detected metastases, and no one with a negative PET scan was positive for cancer on other imaging tests. PET imaging found