FDG-PET/CT in restaging of patients with recurrent breast cancer: possible impact on staging and therapy

We aimed to compare the value of combined positron emission tomography (PET)/CT, PET+CT (viewed side by side), CT alone and PET alone concerning the rTNM stage and influence on therapy in patients with recurrent breast cancer. 44 patients with suspicion of recurrent breast cancer underwent whole-body [18F]-2-fluoro-2-deoxy-d-glucose (FDG)-PET/CT. Images of combined PET/CT, PET+CT, PET alone and CT alone were evaluated by four blinded reader teams. Diagnostic accuracies and influence on therapy were compared. Histology and a mean clinical follow up of 456 days served as the standard of reference. Differences between the staging procedures were tested for statistical significance by McNemar's test. Overall TNM tumour stage was correctly determined in 40/44 patients with PET/CT, in 38/44 with PET+CT, in 36/44 with PET alone and in 36/44 patients with CT alone. No statistically significant difference was detected between all tested imaging modalities. PET/CT changed the therapy in two patients compared with PET+CT, in four patients compared with PET alone and in five patients compared with CT alone. Combined PET/CT appeared to be more accurate in assessing the rTNM and showed a moderate impact on therapy over PET and CT. Minor improvements were noted when compared with PET+CT. Experienced readers might therefore be able to provide accurate staging results for further therapy from separately acquired studies.