Total Lesion Glycolysis on 18F-FDG PET/CT of Women with Non-Locally Advanced Breast Cancer: Does it Correlate with CT Density of the Lesion?

Abstract

Objective: Breast cancer (BC) is the second most frequent malignancy in women. Fluorine-18-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/computed tomography (CT) has become a major diagnostic tool for staging of the disease and predicting the prognosis. We aimed to evaluate the correlation between main quantitative 18F-FDG PET/CT parameters- primarily TLG (total lesion glycolysis), and CT density measurements as Hounsfield Unit (HU) of the primary BC masses in non-locally advanced BC (non-LABC) patients. And also we aimed to see whether there is a correlation between the volume and HU measurements of BC masses in non-LABC patients. Methods: In this retrospective study, we included 17 women with unilateral non-LABC having a mean age of 54.1±10.3 years who underwent 18F-FDG PET/CT before any treatment between 2016−2017. The mean volume, HU, maximum standardized uptake value (SUVmax) and TLG of the primary BC masses with their standard deviations and 95% confidence intervals (CI)s were calculated. Of the BC masses, the correlations between their mean TLG and mean HU, their mean SUVmax and mean HU, their mean volume and mean HU were statistically calculated.Results: The mean volume and HU of BC masses were 4.6±3.9 mL (95% CI: 2.6−6.6) and 42.5±4.1 HU (95% CI: 40.3−44.6), respectively. The mean SUVmax and TLG of BC masses were 6.4±5.6 g/mL (95% CI: 3.5−9.3) and 22.1±14.2 g/mLxmL (95% CI: 14.7−29.4), respectively. Of the BC masses, the correlations between their mean TLG and mean HU (r=-0.443, P=0.075), besides their mean SUVmax and mean HU (r=-0.368, P=0.146) were not statistically significant. The correlation between the mean volume and the mean HU of BC masses was also statistically insignificant (r=-0.214, P=0.410). Conclusion: In women with non-LABC, 18F-FDG PET/CT is a useful and reliable tool for obtaining the TLG of primary BC masses presenting with various CT densities.