Correlation between tumor to liver SUV ratio and molecular subtypes of invasive breast carcinoma in PET CT

Abstract

Background: Breast cancer is known to be one of the most cancer affecting women around the globe and the second most common cancer in general. In third worlds countries, breast cancer is the most cause of cancer death. Early diagnosis and accurate follow-up of these patients affect the management. There are multiple prognostic factors most important one is the immunohistochemical molecular markers in the specimens including human epidermal growth factor, progesterone, and estrogen receptors (HER2, PR, ER). In breast cancer, the HER2 positive molecular subtype is associated with a bad prognosis and aggressive histological features, yet while following neoadjuvant chemotherapy, it achieves an increased pathological complete response rate. 18F-fluoro-2-deoxy-d-glucose positron emission tomography (FDG PET) has proved to be an effective and accurate imaging technique for lymph node and distant metastasis assessment, tumor staging, restaging of recurrence, treatment response, and follow-up. In breast cancer, tumor molecular subtype, tumor size, proliferation index, and histological grade correlated with 18F-fluoro-2-deoxy-d-glucose (FDG) uptake. This study evaluates the possible correlation between tumor to liver and tumor to spleen (standardized uptake value) SUV max ratio and the four different molecular subtypes in patients with pathologically proven primary breast cancer. Results: Tumor to liver and tumor to spleen SUV max ratio (TLR, TSR) was a significant parameter for HER2 molecular subtype identification (P value = 0.0005 and 0.014 respectively) and luminal A molecular subtype identification (P value = 0.016 and 0.037 respectively). The specificity, sensitivity, and area under the receiver operating-characteristic curve (AUC) of TLR parameters for HER2-positive subtype identification were 89.4%, 83.3%, and 0.89, respectively. The specificity, sensitivity, and AUC of the TSR parameter for HER2-positive subtype identification were 57.9%, 100%, and 0.83, respectively. Conclusions: TLR and TSR appeared to be valuable for HER2- and luminal A molecular subtype detection. thus, 18F-FDG PET/CT could be a beneficial tool for prediction of tumor biological characteristics that help in management of breast cancer patients.