Comparison of [68Ga]Ga-PSMA-11 PET/CT with [18F]NaF PET/CT in the evaluation of bone metastases in metastatic prostate cancer patients prior to radionuclide therapy.

Abstract

AIM:

The purpose of this study was to investigate the diagnostic performance of 68Ga-PSMA-11 PET/CT in the evaluation of bone metastases in metastatic prostate cancer (PC) patients scheduled for radionuclide therapy in comparison to [18F]sodium fluoride (18F-NaF) PET/CT.

METHODS:

Sixteen metastatic PC patients with known skeletal metastases, who underwent both 68Ga-PSMA-11 PET/CT and 18F-NaF PET/CT for assessment of metastatic burden prior to radionuclide therapy, were analysed retrospectively. The performance of both tracers was calculated on a lesion-based comparison. Intensity of tracer accumulation of pathologic bone lesions on 18F-NaF PET and 68Ga-PSMA-11 PET was measured with maximum standardized uptake values (SUVmax) and compared to background activity of normal bone. In addition, SUVmax values of PET-positive bone lesions were analysed with respect to morphologic characteristics on CT. Bone metastases were either confirmed by CT or follow-up PET scan.

RESULTS:

In contrast to 468 PET-positive lesions suggestive of bone metastases on 18F-NaF PET, only 351 of the lesions were also judged positive on 68Ga-PSMA-11 PET (75.0%). Intensity of tracer accumulation of pathologic skeletal lesions was significantly higher on 18F-NaF PET compared to 68Ga-PSMA-11 PET, showing a median SUVmax of 27.0 and 6.0, respectively (p < 0.001). Background activity of normal bone was lower on 68Ga-PSMA-11 PET, with a median SUVmax of 1.0 in comparison to 2.7 on 18F-NaF PET; however, tumour to background ratio was significantly higher on 18F-NaF PET (9.8 versus 5.9 on 68Ga-PSMA-11 PET; p = 0.042). Based on morphologic lesion characterisation on CT, 18F-NaF PET revealed median SUVmax values of 23.6 for osteosclerotic, 35.0 for osteolytic, and 19.0 for lesions not visible on CT, whereas on 68Ga-PSMA-11 PET median SUVmax values of 5.0 in osteosclerotic, 29.5 in osteolytic, and 7.5 in lesions not seen on CT were measured. Intensity of tracer accumulation between18F-NaF PET and 68Ga-PSMA-11 PET was significantly higher in osteosclerotic (p < 0.001) and lesions not visible on CT (p = 0.012).

CONCLUSION:

In comparison to 68Ga-PSMA-11 PET/CT, 18F-NaF PET/CT detects a higher number of pathologic bone lesions in advanced stage PC patients scheduled for radionuclide therapy. Our data suggest that 68Ga-PSMA-11 PET should be combined with 18F-NaF PET in PC patients with skeletal metastases for restaging prior to initiation or modification of therapy.

• Authors: Christian Uprimny, Anna Svirydenka, Josef Fritz, Alexander Stephan Kroiss, Bernhard Nilica, Clemens Decristoforo, Roland Haubner, Elisabeth von Guggenberg, Sabine Buxbaum, Wolfgang Horninger, Irene Johanna Virgolini
• Journal: European journal of nuclear medicine and molecular imaging (Eur J Nucl Med Mol Imaging) Vol. 45 Issue 11 Pg. 1873-1883 (10 2018) ISSN: 1619-7089 [Electronic] Germany
• PMID: 29766246 (Publication Type: Comparative Study, Journal Article)

Chemical References

• Fluorine Radioisotopes
• Gallium Isotopes
• Gallium Radioisotopes
• Oligopeptides
• gallium 68 PSMA-11
• Sodium Fluoride
• Edetic Acid
• Fluorine-18

Topics

• Aged
• Aged, 80 and over
• Bone Neoplasms (diagnostic imaging, radiotherapy, secondary)
• Edetic Acid (analogs & derivatives)
• Fluorine Radioisotopes
• Gallium Isotopes
• Gallium Radioisotopes
• Humans
• Male
• Middle Aged
• Oligopeptides
• Positron Emission Tomography Computed Tomography (methods)
• Prostatic Neoplasms (pathology)
• Retrospective Studies
• Sodium Fluoride