FDG PET/CT Volume-Based Quantitative Data and Survival Analysis in Breast Cancer Patients: A Systematic Review of the Literature

Purpose: The study aims to assess the role of SUVs, MTV, TLG, and other FDG PET metric data in predicting the prognosis of patients with newly diagnosed BC. Materials and methods: A systematic review was conducted by using three different databases: Pub- Med, Web of Science, and EMBASE, in the period between January 2011 and May 2021. Studies on the use of FDG PET in BC patients concerning the utility of metric PET data and survival were retrieved. The following keywords were used in diverse combinations: "breast cancer", "18F-FDG", "FDG", "PET", "PET/CT", "FDG PET", "volumetric parameters", "metabolic tumor volume", "MTV", "total lesion glycolysis", "TLG", "prognosis", "prognostic". No limits were applied. The quality of selected papers was assessed by using specific criteria. Results: Totally 123 articles were retrieved, but only 14 studies were selected. In the selected papers, overall, the number of patients was 1850. Overall survival (OS) was the main outcome in three studies, while both OS and disease-free survival (DFS) were considered in the remainder of most papers. PET/CT was performed in patients with BC before surgery or neoadjuvant chemotherapy in 6 studies and in metastatic BC in 8. At multivariable analyses, diverse PET metrics, such as SUVmax, MTV, and TLG, were correlated to recurrence or OS. However, a large heterogeneity for the proposal cut-off, able to discriminate between poor and good prognosis, was found. Conclusion: PET metrics are helpful for the prognosis stratification in patients with locally advanced or metastatic BC. However, no specific cut-off values for these variables are now available in this setting of patients.