Presentation Authors: Gerald Andriole*, Barry Siegel, Saint Louis, MO, . LOCATE Study Group, x, WA
Introduction: Conventional imaging for men with biochemical recurrence after definitive treatment of clinically localized disease is usually normal, especially when prostate specific antigen (PSA) levels are low. Early and precise localization of disease recurrence may guide treatment, leading to a chance of cure when tumor burden is limited and amenable to targeted therapy. _x000D_
18F-Fluciclovine is approved for use with positron emission tomography (PET) in Europe and the USA for men with suspected recurrence of prostate cancer. LOCATE was a prospective trial to assess the impact of 18F-fluciclovine PET/CT findings on management of men with prostate cancer recurrence after curative intent primary therapy and negative/equivocal conventional imaging. Here, we characterize sites of recurrence according to PSA using data from LOCATE, and explore the potential for 18F-fluciclovine PET/CT to evaluate oligometastatic disease.
Methods: Eligible men (â‰¥ 18 y; prior curative intent treatment of prostate cancer; recurrence based on rising PSA; negative/equivocal findings on standard imaging) underwent 18F-fluciclovine PET/CT according to standard protocols. Results were stratified by baseline PSA levels.Oligometastatic disease was defined as 1-5 extraprostatic lesions (â‰¤ 3 lesions in any single organ system) in men with negative prostate/bed imaging (as a surrogate for primary tumour control).
Results: Between June 2016 and May 2017, 213 patients (median PSA 1.0 ng/mL, 164 [77%] prior prostatectomy) were scanned. As shown in the table, 18F-fluciclovine PET/CT detected lesions in 122 (57%) men. Patient level and pelvic region detection rates were broadly proportional to baseline PSA. At PSA < 1.0 ng/mL, substantial detection was noted in pelvic nodes (9.3%), retroperitoneal nodes (5.6%) and bone (6.5%)._x000D_
In total, 53/213 (25%) had oligometastatic disease; 52 (24%) with 1-3 metastases and 1 (0.5%) with 5 metastases. Twenty (38%) of the oligometastatic patients had PSA â‰¤ 1.0 ng/mL.
Conclusions: Even at low PSA levels, 18F-fluciclovine PET/CT identified a diverse pattern of recurrence missed with conventional imaging. One quarter of men had oligometastatic disease raising the potential for 18F-fluciclovine PET/CT to guide targeted treatment of oligometastases.
Source of Funding: Blue Earth Diagnostics