Researchers are warning clinicians about a serious flaw in PET imaging of prostate-specific membrane antigen (PSMA) that could result in a misdiagnosis for prostate cancer, according to a paper published in the September issue of the Journal of Nuclear Medicine.
Previous studies have found that benign tissue in the kidneys, bowels, salivary glands, and ganglia could increase PSMA expression. This, in turn, could lead to the misidentification of lymph node metastases, an inaccurate diagnosis, and an unnecessary change in therapy regimen.
In the current study, the researchers, led by Dr. Christoph Rischpler from the department of nuclear medicine at the Technical University of Munich in Germany, explored PSMA ligand uptake in cervical, celiac, and sacral ganglia in 407 patients, comparing the findings to adjacent lymph node metastases. In those areas, they saw that uptake was greater than background levels in 401 patients (98.5%) (JNM, September 2018, Vol. 59:9, pp. 1406-1411).
They recommended that nuclear medicine physicians analyze PSMA-ligand uptake along with the exact localization and configuration of the respective lesion to differentiate expressive ganglia from lymph node metastases and to avoid misinterpretation.
"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," Rischpler said. "We hope that an increased awareness among nuclear medicine physicians of this important pitfall helps to increase diagnostic accuracy and improve therapy guidance, preventing unnecessary procedures for prostate cancer patients."
