Initial Fludeoxyglucose (18F) Positron Emission Tomography-Computed Tomography (FDG-PET/CT) Imaging of Breast Cancer - Correlations with the Primary Tumour and Locoregional Metastases.

Backround: We aimed to evaluate initial PET/CT features of primary tumour and locoregional metastatic lymph nodes (LNs) in breast cancer and to look for potential relationships between several parameters from PET/CT.

Material/methods: Twenty-three women (mean age; 48.66±12.23 years) with a diagnosis of primary invasive ductal carcinoma were included. They underwent PET/CT imaging for the initial tumour staging and had no evidence of distant metastates. Patients were divided into two groups. The LABC (locally advanced breast cancer) group included 17 patients with ipsilateral axillary lymph node (LN) metastases. The Non-LABC group consisted of six patients without LN metastases. PET/CT parameters including tumour size, axillary LN size, SUV of ipsilateral axillary LNs (SUV-LN), SUV of primary tumour (SUV-T) and NT ratios (SUV-LN/SUV-T) were compared between the groups. Correlations between the above-mentioned PET/CT parameters in the LABC group as well as the correlation between tumour size and SUV-T within each group were evaluated statistically.

Results: The mean values of the initial PET/CT parameters in the LABC group were significantly higher than those of the non-LABC group (p<0.05). The correlation between tumour size and SUV-T value within both LABC and non-LABC groups was statistically significant (p<0.05). In the LABC group, the correlations between the size and SUV-LN values of metastatic axillary LNs, between tumour size and metastatic axillary LN size, between SUV-T values and metastatic axillary LN size, between SUV-T and SUV-LN values, and between tumour size and SUV-LN values were all significant (p<0.05).

Conclusions: We found significant correlations between PET/CT parameters of the primary tumour and those of metastatic axillary LNs. Patients with LN metastases had relatively larger primary tumours and higher SUV values.