Comparison of the Volumetric and Radiomics Findings of 18F-FDG PET/CT Images with Immunohistochemical Prognostic Factors in Local/locally Advanced Breast Cancer

Objective: The aim of this study was to determine the change in volumetric and radiomics parameters of fluorine-18 fluorodeoxyglucose (F-FDG) PET/computed tomography (CT) imaging in local/locally advanced cancer patients according to immunohistochemical findings.

Patients And Methods: A total of 72 patients who were diagnosed with local/locally advanced breast cancer and then examined by F-FDG PET/CT for staging were included in this study. Immunohistochemical prognostic factors [estrogen receptor (ER), progesterone receptor (PR), human epidermal growth factor receptor 2 (Her-2), p53 mutation, Ki-67 proliferation index] and histological grades were determined. Standardized uptake value (SUV)-based, volume-based, and radiomics findings were obtained from F-FDG PET/CT images.

Results: In cases of ER and PR negativity, Her-2 positivity, presence of the p53 mutation, and Ki-67 index of at least 20% patients, total volumetric parameters were significantly higher in paired comparisons. The results of the ER-negative group were significantly higher than those of ER-positive patients in GLRLM_GLNU, GLRLM_RLNU, GLZLM_GLNU, and GLZLM_ZLNU comparisons. In grade 3 patients, mean SUV, maximum SUV, and GLRLM_LRHGE values were higher than those of grade 2 patients. SUV and volumetric parameters were significantly higher in patients with Ki-67 index of at least 20% than those with less than 20%. Maximum SUV, breast tumor lesion glycolysis values, and entropy in nuclear polymorphism in the 3+ patient group were found to be higher compared with the 2+ patient group. Moreover, patients with mitosis 3+ had significantly higher breast metabolic tumor volume, breast tumor lesion glycolysis, and kurtosis values than the 1+ group.

Conclusion: ER negativity, triple negativity, high tumor grade, and high nuclear polymorphism were associated with tumor heterogeneity. With respect to ER negativity, PR negativity, high tumor grade, high mitosis number, high Ki-67 index, Her-2 positivity, and the presence of p53 mutation, an increased tumor load were observed. In addition to immunohistochemical parameters, the use of radiomics data is believed to contribute to breast cancer management.