Advances on correlation of PET-CT findings with breast cancer molecular subtypes, treatment response and prognosis

Abstract

In recent years, PET-CT has an increasing importance in the diagnosis and treatment of breast cancer. PET-CT scan can be used as a noninvasive method for molecular subtyping of breast cancer, and prediction of therapeutic effect and prognosis of patients. Studies have revealed that luminal A subtype has a significantly lower maximum standard intake value (SUVmax) than the other subtypes; triple-negative and human epidermal growth factor receptor 2 (HER2) positive tumors have relatively high SUVmax than luminal B subtype, but the specificity and sensitivity of SUVmax in diagnosis of molecular subtypes are very low, so its clinical application is limited. In predicting the effectiveness of the treatment and the prognosis of the patients, the decreased uptake of fluorodeoxyglucose (FDG) is correlated with better therapeutic effect. In addition, patients with high FDG uptake have worse survival outcomes. New tracers, such as 18F-fluoroestradiol (18F-FES) and[89Zr]trastuzumab play an important role in molecular subtyping of breast cancer. 18F-FES PET-CT can effectively evaluate the estrogen receptor (ER) status of breast cancer and the response to endocrine therapy.[89Zr]trastuzumab PET-CT can evaluate the expression of HER2 and localization of HER2-overexpressing tumors, but their specificities and sensitivities are also low. In this article, we review the recent advances on the correlation of PET-CT findings with molecular subtypes, treatment response and prognosis of breast cancer.