LAUSR

Prostate-Specific Membrane Antigen Positron Emission Tomography/Computed Tomography in Locally Advanced, Recurrent, and Metastatic Prostate Cancer To the Editor We read with great interest the recent article by Lindenberg et al.1 We commend the authors on a timely and comprehensive review in this important topic. However, there are several inconsistencies and inaccuracies that we believe necessitate clarification. First, the authors highlight the naive nature of gallium citrate (68Ga) prostate-specific membrane antigen (PSMA) positron emission tomography/computed tomography (PET/CT) in current practice and discuss that histological validation is incomplete. However, in a recent meta-analysis published by our group,2,3 we identified 11 studies reporting histopathological correlation with 68Ga PSMA PET/CT. Of these, only 5 studies, representing 239 patients, were suitable for analysis due to the nature of the respective methodologies. From this, on perpatient–based analysis, the sensitivity, specificity, and positive and negative predictive value were 86%, 86%, 83%, and 89%, respectively. Similarly, on per-lesion–based analysis, the sensitivity, specificity, and positive and negative predictive values were 80%, 97%, 82%, and 97%, respectively. While more mature data are required to definitively determine the true sensitivity and specificity profile of 68Ga PSMA PET/CT, these metaanalytical data provide a useful indicator for clinicians. Furthermore, recent data correlating lymph node histopathologic analysis with PSMA PET/CT findings add further to the evidence base for PSMA PET/CT as the most promising of PET tracers in prostate cancer. Second, Lindenberg et al1 suggest that 68Ga PSMA PET CT is “not yet commercially available and [is] only used in research protocols.” While this may reflect the US experience, this is not the case globally. Currently, PSMA PET/CT has been widely embraced internationally including across Asia, Australia, and Europe. Indeed, in our experience in Australia, most of the 68Ga PSMA PET/CTs performed are for publicly and privately funded patients in routine clinical practice. The utility of this tool has even been demonstrated in regional Australia, with a group reporting that PSMA PET/CT changed management in 53.7% of patients receiving radiotherapy.4 Undoubtedly, 68Ga PSMA PET/CT represents a promising diagnostic tool in the armamentarium of clinicians in the setting of primary and recurrent prostate cancer, and it is clear that this is in widespread clinical use outside of research protocols.5 While uptake and availability of 68Ga PSMA PET/CT in the Americas is limited, the global experience is considerable and should be acknowledged.