Potential utility of early metabolic response by 18F-2-fluoro-2-deoxy-d-glucose-positron emission tomography/computed tomography in a selected group of breast cancer patients receiving preoperative chemotherapy

IntroductionTo assess 18F-2-fluoro-2-deoxy-d-glucose-positron emission tomography/computed tomography’s (18F-FDG-PET/CT) potential clinical utility to allow early treatment changes during preoperative chemotherapy (PCT) in patients with early/locally advanced breast cancer (BC).Patients and methodsSixty newly diagnosed early/locally advanced BC patients received 6–8 cycles of PCT. Optimal pathologic response (pR) was the absence of cancer cells in breast and axillary lymph nodes. All other conditions were defined as pathologic non-response (pNR). 18F-FDG-PET/CT maximum standardised uptake value (SUVmax) was measured at baseline and after 2 cycles of PCT. Metabolic response was defined as SUVmax percentage changes (Δ-SUV) >50% and was compared with pR rates.ResultsThirteen (22%) patients achieved pR; according to immunohistochemistry, 16% of ER-positive/HER2-negative patients, 29% and 27% of HER2-positive and triple negative patients respectively achieved pR. 18F-FDG-PET/CT showed the highest specificity (38%) and negative predictive value (100%) in ER-positive/HER2-negative patients. In this subgroup, at a median follow-up of 36.6 months, median disease-free survival was still not reached in metabolic responders while it was 37 months in metabolic non-responders (p = 0.049).DiscussionEarly metabolic non-response was always associated to pNR and poor prognosis in ER-positive/HER2-negative patients. In this subgroup, 18F-FDG-PET/CT might be useful to select patients who will probably benefit from early therapeutic strategy modifications.