The role of (18)F-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography (PET/CT) in patients with breast cancer recurrence: a comparison to conventional imaging (CI) techniques and clinical impact on patient management

AIM: The aim of this study was to evaluate the impact of PET/CT on clinical management in patients with breast cancer recurrence and compare PET/CT data with CI data (US, ceCT, MR).METHODS: we observed 70 consecutive patients (age 60.25 ± 6.2 yo) addressed to PET/CT scan from January 2015 to April 2016 for suspected re- currence of previously staged and treated breast cancer. All patients were studied with the same high performing PET/CT scanner with innovative image reconstruction algorithm (integrating parameters de- rived from “Point Spread Function” and “Time Of Flight” calcula- tions). PET/CT findings were compared with CI data on a patient basis. RESULTS: in 21 patients (30.0%) PET/CT revealed recurrence of breast cancer in the region of the primary tumor; CI detected local recurrence in 16 patients (22.9%) [p=ns]. In 2 cases (2.8%) PET/CT showed a focal radiotracer uptake in the contralateral mammary gland (final histology showed malignant tumor involvement). In 21 patients (30.0%) PET/CT showed lymph node metastases in the primary breast tumor ipsilateral axilla, while CI managed to do so in 15 (21.4%) [p<0.35]. Furthermore PET/CT showed lymph node disease relapse in other basins in 39 patients (55.7%) while CI in 23 (32.8%) [p<0.1]. Bone metastases were detected by PET/CT in 28 patients (40%) while by ceCT in 12 (17.4%) [p<0.01]. Lung involvement was detected by PET/CT in 17 cases (24.2%) while by ceCT in 15 (21.4%) [p=ns]. PET/CT showed liver metastases in 9 cases (12.8%) while CI in 8 (11.4%) [p=ns]. Adrenal metastases were seen on PET/ CT in 6 cases (8.5%) while on CI in 3 (4.2%) [p<0.106]. In 22 patients (31.4%), PET/CT detected additional lesions not visible on CI. PET/CT had an impact on clinical management in 37 patients (52.8%) by detecting more extensive loco-regional disease or distant metastases. In 21 patients (30.0%) extensive surgery was not under- taken and treatment was changed (CHT and/or RT). The sensitivity, specificity, accuracy, positive and negative predictive values of PET/ CT were respectively 97%, 92%, 95%, 94% and 96%. CONCLUSIONS: PET/CT proved to play an important role in restaging patients with breast cancer recurrence since its results changed the clinical management in a large percentage of patients. PET/CT showed better performance than CI in all evaluated recurrence sites -although the difference was mainly not statistically significant- therefore it could potentially replace conventional imaging in restaging patients with breast cancer recurrence -especially concerning bone involvement- to optimize diagnostic timing and even costs.