Abstract
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Objectives Anti-3-[18F]FACBC is a synthetic amino-acid analog with utility in differentiating prostatic from extra-prostatic recurrence of prostate cancer. As part of an ongoing prospective randomized trial in patients with biochemical recurrence post prostatectomy, we examined changes in radiotherapy (RT) treatment decisions and treatment volume using anti-3-[18F]FACBC PET-CT (FACBC) guidance.
Methods In a preliminary analysis, RT treatment decisions made based on FACBC results were evaluated and compared to those planned pre-FACBC. Descriptive statistics were computed. McNemar and Stuart-Maxwell tests were used to compare changes in pre and post FACBC RT treatment decisions as applicable.
Results 24/54 patients had salvage radiotherapy after randomization to receive FACBC. Mean age (±SD, range) was 62.5 (±8.8, 42-75), mean PSA (±SD, range) was 1.8 ng/ml (±3.0, 0.07-11.2). Of these 24 patients, the initial decision was to recommend RT to the prostate bed (PB) only in 16 cases and to the prostate bed and pelvis (PB-P) in 8 cases. FACBC was positive in 21/24 cases: PB only in 9 patients; PB-P in 11 patients; PB-P and extra-pelvis in 1 patient. As a result of FACBC findings, the decision to offer RT was withdrawn in 1/24 patient (4.2%; P= 0.31). FACBC changed treatment volumes in 6/24 patients from PB only to PB P (25%; P=0.01). Overall, FACBC altered the RT decision in 7/24 patients (29.2%; P=0.03). Although the mean PSA in those with treatment decision changes was slightly higher than those without, the difference was not statistically significant (2.2 vs. 1.6 ng/ml; P=0.21).
Conclusions Use of advanced molecular imaging with FACBC resulted in a 29% change in radiotherapy management decisions.
Research Support Research sponsored by the NIH (R01 CA169188-01) and Blue Earth Diagnostics