Researchers at the UCLA Health Jonsson Comprehensive Cancer Center have found that metastases of non-metastatic hormone-sensitive prostate cancer that previously went undetected can be recognized using a special PET scan technology.
With traditional scans, prostate cancer is often classified as non-metastatic, when in reality the patient has the metastatic variant. The U.S. research has now shown that using an advanced PSMA-PET scan, or prostate-specific membrane antigen-positron emission tomography, to be evaluated, the correct, metastatic, classification can be diagnosed much earlier.
“Our study demonstrates the crucial role of PSMA-PET in accurately mapping prostate cancer, which can greatly impact treatment decisions and outcomes,” said Dr. Jeremie Calais, author of the study and senior lecturer in the department of molecular and medical pharmacology at UCLA's David Geffen School of Medicine.
PSMA-PET
PSMA-PET imaging uses tiny amounts of radioactive “tracers,” called radiotracers, that bind to prostate cancer cells, making them visible on PET scans. This advanced imaging technology is redefining the way prostate cancer is treated. Unlike conventional imaging, which provides only anatomical details, PSMA-PET provides functional imaging that shows the biological activity of the cancer, which can significantly improve the accuracy of disease staging.
The clinical application of PSMA-PET has changed the landscape of prostate cancer imaging, but treatment decisions often depend on clinical trials in which this advanced imaging technique was not used for patient selection.
The U.S. researchers are not the only ones exploring the potential of PSMA-PET scanning technology. A few months ago, we reported on the PhD of urologist-in-training Joris Heetman. With his doctoral research, he also already demonstrated that the PSMA PET/CT scan method has proven to be able to find tumors that would otherwise go undetected and may only be seen at a later stage, when the cancer is more advanced.
Post-hoc study
To better understand the advantages of PSMA-PET over conventional imaging, the researchers conducted a post-hoc, retrospective cross-sectional study. To do so, data from 182 patients with high-risk recurrent prostate cancer whose disease was thought to be confined to the prostate were used.
These were all patients who were also previously eligible for the EMBARK study. That previously showed that addition of enzalutamide, a type of hormone therapy, to androgen deprivation therapy significantly improves metastasis-free survival. However, the study relied on conventional imaging to classify patients, leading the researchers to believe that the extent of the disease was underestimated in some cases.
Substantially more metastases detected
In the patient cohort, the researchers found that PSMA-PET detected cancer metastases in nearly half (46%) of the patients, even though traditional imaging did not indicate cancer metastases. In fact, based on PSMA-PET, nearly a quarter (24%) of patients showed five or more lesions that had been missed by conventional imaging.
Although the current findings underscore the potential of PSMA-PET, researchers continue to explore its broader applications through additional studies. More research is needed to understand its impact on long-term patient outcomes and how it can best guide therapy, Calais said.
