PSMA PET may lead to misdiagnosis, unnecessary changes in treatment

PET imaging is a common tool to establish the stage of a patient’s prostate cancer, but new research raises questions about its association with misdiagnosis and unnecessary changes in therapies. Benign tissues in the kidney, bowels and salivary glands may show increased prostate-specific membrane antigen (PSMA) expression, prompting experts to caution against relying solely on PSMA PET.

"It is important that nuclear medicine physicians be aware of this pitfall, as the interpretation of PSMA PET scans may have a substantial impact on therapy guidance," said Christoph Rischpler, MD, of Germany's Technical University in Munich, in a statement from the Society of Nuclear Medicine & Molecular Imaging. His team’s findings were published online Sept. 7 in the Journal of Nuclear Medicine.

Researchers, in looking at 407 patients and comparing findings to adjacent lymph node metastases, found the uptake was above background levels in 401 (98.5 percent) participants.

 

Despite the high rate of uptake, PSMA PET is still a valuable tool in diagnosing prostate cancer and determining its stage of development. These findings, according to the authors, mean physicians should be aware that misinterpretations based on benign tissues are possible.  

“[PSMA]-ligand uptake in sympathetic ganglia is a very common and important pitfall,” Rischpler et al. wrote. “However, on the basis of different anatomic configuration and uptake characteristics (intensity and intraindividual correlation of uptake), differentiation from possible adjacent lymph node metastases should be easily accomplishable.”

Watch a video of Rischpler summarizing findings from his team of researchers here.