Comparative analysis of contemporary and past PSMA PET/CT results for recurrent prostate cancer in a high-volume Brazilian center.

Abstract

51 Background: PSMA PET/CT scan (68Ga-PSMA PET/CT) has emerged as a highly accurate tool when assessing disease staging both for newly diagnosed localized high-risk prostate cancer and for recurrent disease, with treatment plan modification in up to two-thirds of patients. PSMA PET/CT is commercially available in Brazil since last decade and growing experience with this test has led to a more accurate analysis of the results over the years. Methods: We retrospectively reviewed the PSMA PET/CT scans results of patients undergoing the exam in all disease stages in a single institution in Brasilia, Brazil, between October 2015 and July 2022 and analyzed the results correlated with clinicopathological information (when available) in two separated timeframes for those in the recurrent disease setting. Results: Overall, more than 2,500 PSMA PET-CT scans were performed since October 2015. Between 2015 and 2019, 351 exams were performed, of which 303 in the setting of recurrent disease, while 297 tests were executed between 2021 and 2022, with 283 of them being done in the recurrent disease setting. Any clinicopathological information was available for 648 patients, of whom 586 underwent the test in the setting of recurrent disease following treatment of primary disease. Conclusions: There was a similar positivity rate among the clinicopathological characteristics analyzed in an indirect comparison of the two timeframes. It is remarkable the increased positivity rate among patients with lower levels of PSA in the contemporary dataset, which may reflect the learning curve of this image method. Among patients selected by Gleason grade, no definitive information can be extracted given the distinct PSA levels between patients in the two selected timeframes. [Table: see text]