68Ga-PSMA-HBED-CC PET for differential diagnosis of suggestive lung lesions in patients with prostate cancer

Thomas Pyka, Gregor Weirich, Ingo Einspieler, Tobias Maurer, Jörg Theisen, Georgios Hatzichristodoulou, Kristina Schwamborn, Markus Schwaiger, Matthias Eiber

Research output: Contribution to journalArticlepeer-review

95 Scopus citations

Abstract

In prostate cancer (PC) patients, the differentiation between lung metastases and lesions of different origin, for example, primary lung cancer, is a common clinical question. Herein, we investigated the use of Glu-NH-CO-NH-Lys(Ahx)-HBED-CC (68Ga-PSMA-HBED-CC) for this purpose. Methods: PC patients (n 5 1,889) undergoing 68Ga-PSMA PET/CT or PET/MR scans were evaluated retrospectively for suggestive lung lesions. For up to 5 lesions per patient, location, CT diameter, CT morphology, and SUVmax were determined. The standard for classification was either histopathologic evaluation or, in the case of PC metastases, responsivity to antihormone therapy. A comparison of the different classes was executed by Student t test. Prostate-specific antigen and prostate-specific membrane antigen (PSMA) immunohistochemistry were performed if histologic samples were available; 68Ga-PSMA autoradiography was performed on an exemplary case of PET-positive lung cancer. Results: Eighty-nine lesions in 45 patients were identified, of which 76 were classified as PC (39 proven, 37 highly probable), 7 as primary lung cancer, and 2 as activated tuberculosis; 4 lesions remained unclear. The mean SUVmax was 4.4 ± 3.9 for PC metastases and 5.6 ± 1.6 for primary lung cancer (P = 0.408). Additionally, substantial differences in SUVmax intraindividually were detected. The 2 tuberculous lesions showed an SUVmax of 7.8 and 2.5. Using immunohistochemistry, we could demonstrate PSMA expression in the neovasculature of several PSMA PET-positive lung cancers as well as in tuberculous lesions from our histologic database. Conclusion: Quantitative (SUV) analysis of 68Ga-PSMA PET was not able to discriminate reliably between pulmonary metastases and primary lung cancer in PC patients. The reason for the unexpectedly high tracer uptake in non-PC lesions is not completely clear. PSMA expression in neovasculature provides a possible explanation for this finding; however, other contributing factors, such as tracer binding to proteins other than PSMA, cannot be excluded at present.

Original languageEnglish
Pages (from-to)367-371
Number of pages5
JournalJournal of Nuclear Medicine
Volume57
Issue number3
DOIs
StatePublished - 1 Mar 2016
Externally publishedYes

Keywords

  • Ga-PSMA
  • Lung cancer
  • Prostate cancer
  • Pulmonary metastasis

Fingerprint

Dive into the research topics of '68Ga-PSMA-HBED-CC PET for differential diagnosis of suggestive lung lesions in patients with prostate cancer'. Together they form a unique fingerprint.

Cite this