Relationships of 18F-FDG uptake by primary tumors with prognostic factors and molecular subtype in ductal breast cancer

Abstract Objectives In this study, we aimed to investigate the correlation between SUVmax of primary tumor and prognostic factors/molecular subtype in ductal breast cancer patients. Materials and methods We retrospectively reviewed 150 female patients with pathologically proven invasive ductal breast cancer from January 2015 to October 2019 who underwent 18F-FDG PET/CT for initial staging. Histopathological prognostic features of the primary tumor (histological grade, hormone receptor status, Ki-67 index, vb.) were obtained from the tru-cut biopsy report. In 18F-FDG PET/CT studies, the maximum standardized uptake value (SUVmax) of the primary breast tumor was calculated and compared with the presence of axillary lymphadenopathy and/or distant metastases, histopathological prognostic factors and molecular subtype. Results The high SUVmax of primary breast tumors is significantly correlated with the clinicopathological factors: high tumor size, high histologic grade, high Ki-67 index, axillary lymph node positivity and distant metastasis. SUVmax value was significantly higher in patients with basal subtype than patients with Luminal A subtype (8,14 ± 3,71 and 4,64 ± 2,45, p = 0,002). Correlation analysis revealed a low correlation between Ki-67 index and SUVmax (r = 0,276, p = 0,001) and moderate correlation between tumor size and SUVmax (r = 0,470, p = 0,001). In multivariate linear regression analysis, Ki-67 index and tumor size had a statistically significant effect on SUVmax values. As these parameters increase, it is seen that it increases SUVmax values (p = 0,004, Std Beta: 0,228, 95% CI:0,010–0,055 and p = 0,001, Std Beta:0,374, 95% CI:0,55–0,136, respectively). Conclusion High SUVmax value is associated with factors suggesting poor prognosis. Pretreatment 18F-FDG PET/CT can be used as a tool to predict prognosis in breast cancer.