Dual time point 18F-fluorodeoxyglucose positron emission tomography/computed tomography fusion imaging (18F-FDG PET/CT) in primary breast cancer

<jats:title>Abstract</jats:title><jats:sec> <jats:title>Background</jats:title> <jats:p>To evaluate the clinicopathological and prognostic significance of the percentage change between maximum standardized uptake value (SUV<jats:sub>max</jats:sub>) at 60 min (SUV<jats:sub>max</jats:sub>1) and SUV<jats:sub>max</jats:sub> at 120 min (SUV<jats:sub>max</jats:sub>2) (ΔSUV<jats:sub>max</jats:sub>%) using dual time point <jats:sup>18</jats:sup>F-fluorodeoxyglucose emission tomography/computed tomography (<jats:sup>18</jats:sup>F-FDG PET/CT) in breast cancer.</jats:p> </jats:sec><jats:sec> <jats:title>Methods</jats:title> <jats:p>Four hundred and sixty-four patients with primary breast cancer underwent <jats:sup>18</jats:sup>F-FDG PET/CT for preoperative staging. ΔSUV<jats:sub>max</jats:sub>% was defined as (SUV<jats:sub>max</jats:sub>2 − SUV<jats:sub>max</jats:sub>1) / SUV<jats:sub>max</jats:sub>1 × 100. We explored the optimal cutoff value of SUV<jats:sub>max</jats:sub> parameters (SUV<jats:sub>max</jats:sub>1 and ΔSUV<jats:sub>max</jats:sub>%) referring to the event of relapse by using receiver operator characteristic curves. The clinicopathological and prognostic significances of the SUV<jats:sub>max</jats:sub>1 and ΔSUV<jats:sub>max</jats:sub>% were analyzed by Cox’s univariate and multivariate analyses.</jats:p> </jats:sec><jats:sec> <jats:title>Results</jats:title> <jats:p>The optimal cutoff values of SUV<jats:sub>max</jats:sub>1 and ΔSUV<jats:sub>max</jats:sub>% were 3.4 and 12.5, respectively. Relapse-free survival (RFS) curves were significantly different between high and low SUV<jats:sub>max</jats:sub>1 groups (<jats:italic>P</jats:italic> = 0.0003) and also between high and low ΔSUV<jats:sub>max</jats:sub>% groups (<jats:italic>P</jats:italic> = 0.0151). In Cox multivariate analysis for RFS, SUV<jats:sub>max</jats:sub>1 was an independent prognostic factor (<jats:italic>P</jats:italic> = 0.0267) but ΔSUV<jats:sub>max</jats:sub>% was not (<jats:italic>P</jats:italic> = 0.152). There was a weak correlation between SUV<jats:sub>max</jats:sub>1 and ΔSUV<jats:sub>max</jats:sub>% (<jats:italic>P</jats:italic> < 0.0001, <jats:italic>R</jats:italic><jats:sup>2</jats:sup> = 0.166). On combining SUV<jats:sub>max</jats:sub>1 and ΔSUV<jats:sub>max</jats:sub>%, the subgroups of high SUV<jats:sub>max</jats:sub>1 and high ΔSUV<jats:sub>max</jats:sub>% showed significantly worse prognosis than the other groups in terms of RFS (<jats:italic>P</jats:italic> = 0.0002).</jats:p> </jats:sec><jats:sec> <jats:title>Conclusion</jats:title> <jats:p>Dual time point <jats:sup>18</jats:sup>F-FDG PET/CT evaluation can be a useful method for predicting relapse in patients with breast cancer. The combination of SUV<jats:sub>max</jats:sub>1 and ΔSUV<jats:sub>max</jats:sub>% was able to identify subgroups with worse prognosis more accurately than SUV<jats:sub>max</jats:sub>1 alone.</jats:p> </jats:sec>