18F-FDG uptake in breast cancer correlates with immunohistochemically defined subtypes

To determine whether a correlation exists between maximum standardized uptake value (SUVmax) on 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) and the subtypes of breast cancer. This retrospective study involved 548 patients (mean age 51.6 years, range 21-81 years) with 552 index breast cancers (mean size 2.57 cm, range 1.0-14.5 cm). The correlation between 18F-FDG uptake in PET/CT, expressed as SUVmax, and immunohistochemically defined subtypes (luminal A, luminal B, human epidermal growth factor receptor 2 (HER2) positive and triple negative) was analyzed. The mean SUVmax value of the 552 tumours was 6.07 ± 4.63 (range 0.9-32.8). The subtypes of the 552 tumours were 334 (60 %) luminal A, 66 (12 %) luminal B, 60 (11 %) HER2 positive and 92 (17 %) triple negative, for which the mean SUVmax values were 4.69 ± 3.45, 6.51 ± 4.18, 7.44 ± 4.73 and 9.83 ± 6.03, respectively. In a multivariate regression analysis, triple-negative and HER2-positive tumours had 1.67-fold (P < 0.001) and 1.27-fold (P = 0.009) higher SUVmax values, respectively, than luminal A tumours after adjustment for invasive tumour size, lymph node involvement status and histologic grade. FDG uptake was independently associated with subtypes of invasive breast cancer. Triple-negative and HER2-positive breast cancers showed higher SUVmax values than luminal A tumours. circle 18 F-FDG PET demonstrates increased tissue glucose metabolism, a hallmark of cancers. (orig.)