816P - 68Ga-PSMA-PET/CT as a changing practice tool in biochemically recurrent prostate cancer

Abstract

Background: PSMA-PET/CT have demonstrated interesting results in the detection of loco-regional and distant disease in prostate cancer patients with biochemical relapse. Even with low levels of PSA, PSMA imaging is able to identify metastatic lesions, being a possible tool for tailoring treatment decisions. This study aims to describe the use of PSMA-PET/CT in the daily practice and its clinical impact in the management of prostate cancer patients who have rising PSA after curative treatment. Methods: We performed a retrospective analysis in 29 localized prostate cancer patients of three private Brazilian cancer institutions who underwent PSMA-PET/CT for rising PSA after treatment with curative intent. The clinical impact of PSMA-PET/CT was evaluated by whether the assistant physician changed or not the treatment strategy based solely on PSMA results. In addition, modifications related to local (salvage radiotherapy [SRT], salvage lymphadenectomy [SL]) and systemic (antiandrogen deprivation therapy [ADT], chemotherapy [chemo]) treatment were described. Results: In total, 29 patients were enrolled. Twenty-seven (93%) had undergone radical prostatectomy, and 2 (7%) radiotherapy as the local curative treatment. Sixteen cases (55%) had not received any radiotherapy previously. The mean Gleason score, PSA level and PSADT at time of the examination were 8, 4.2 (0,05-41) ng/ml and 4.4 (0.4-27) months, respectively. PSMA-PET/CT detected at least one suspicious lesion for prostate cancer in 21/29 (58%) patients. Overall, 15/29 (51%) patients had their treatment strategy changed due to results in PSMA imaging. In only 3/29 (10%) the modifications were related exclusively to systemic protocols (1 avoided ADT, 1 added ADT and, 1 added chemo). Whereas in the 12/29 (41%) remaining cases, treatment strategy change involved local treatment. Of these 12 with a local treatment change, 7 added (6 SL, 1 SRT) and 5 avoided (5 SRT) local therapies. Conclusions: Half of the patients with biochemical relapse that underwent PSMA-PET/CT had their treatment protocol changed, most changes related to local treatment. Although the role of PSMA imaging is not clearly defined, PSMA-PET/CT has been used as a practice changing tool in the daily practice. Legal entity responsible for the study: Instituto COI Funding: None Disclosure: All authors have declared no conflicts of interest.