The Clinical Impact of the Late Imaging with 18F-Fluorodeoxyglucose PET Texture Analysis in Invasive Lobular Breast Cancer
Fikri Okan FALAY1,Hülya SEYMEN1
1Department of Nuclear Medicine, Molecular Imaging and Treatment, Koç University Faculty of Medicine, Istanbul-Turkey DOI : 10.5505/tjo.2021.2767 OBJECTIVE
Breast invasive lobular cancer (ILC) is one of the most difficult malignancies to diagnose and follow-up due to its tumor morphology. Tumor heterogeneity is the most important reason for treatment failure and diagnostic limitation. Identification of heterogeneity by a non-invasive method, texture analysis that can be done from positron emission tomography (PET), MR, and CT is developed. In ILC, diagnostic sensitivity is lower with 18F-fluorodeoxyglucose ([18F] FDG) PET/CT compared to invasive ductal carcinoma (IDC). In this study, the correlation between histopathological variables and the texture analysis of [18F] FDG PET/CT standard images, and also late images whose contribution to the diagnosis of many malignancies has been investigated are researched.

Twenty ILC patients underwent standard and late [18F] FDG PET/CT imaging for staging between May 2007 and December 2018. T and N stages, histological and nuclear grades, estrogen receptor, progesterone receptor, human epidermal growth factor-2, and Ki-67 were recorded.

Thirty-two textural indices with conventional and formal indices and histogram values were calculated with LIFEx software to find heterogeneity in standard and late [18F] FDG PET/CT images. Conventional and discrete indices based on GLRM and GLZM are more correlated than other texture indices. Greater number of significantly correlations was found between histopathological variables and texture analysis of late imaging (p<0.05).

In our study, the conventional indices, especially in the 2nd degree indices, in the texture analysis performed with [18F] FDG PET/CT significantly correlated in the ILC, which has lower [18F] FDG affinity compared to IDC due to the tumoral tissue characteristics. Although the presence of more correlations with histopathological prognostic information in late images suggests a greater diagnostic contribution, further studies with more numbers are needed. Keywords : [18F] FDG PET/CT; breast cancer; late imaging; texture analysis