Superiority of 68Ga-FAPI PET/CT scan in detecting additional lesions compared to 18FDG PET/CT scan in breast cancer

Purpose We compared the ability of 68 Ga-FAPI PET//CT with 18 FDG PET/CT imaging techniques to detect additional lesions in breast cancer patients that may affect further chemotherapy options. Methods A total of 48 patients with breast cancer underwent concurrent 68 Ga-FAPI-04 and 18 FDG PET/CT regardless of whether they had received chemotherapy or not in the last month before imaging. Both modalities were compared according to various parameters: clinical/pathological features, number of lesions detected, activity uptake (SUV max ), and the effect on the evaluation of response to treatment in the post-chemotherapy group. Results This retrospective study included 48 patients with breast cancer (mean age 53.3 ± 11.7 years; IDC 89.6%; ILC 10.4%). In the comparison of both modalities, no statistical significance was obtained in terms of the pathological characteristics of the patients. More lesions were demonstrated in all categorized regions in 68 Ga-FAPI PET/CT imaging with higher uptake values compared to 18 FDG PET/CT in this study. In the treatment response evaluation of the post-chemotherapy group, 12 cases (12/24) who were evaluated as PMR, CMR, or SD according to 18 FDG PET/CT results were later accepted as PD due to newly detected lesions in complementary 68 Ga-FAPI PET/CT imaging and treatment of patients was managed accordingly by clinicians. Conclusion It was determined that 68 Ga-FAPI PET/CT was superior to 18 FDG PET/CT in terms of accuracy and it was thought that 68 Ga-FAPI PET/CT could be utilized as an additional complementary imaging to 18 FDG PET/CT. Moreover, 68 Ga-FAPI PET/CT, with its significant theranostic potential, could become a key element in predicting the pathological response of breast cancer patients in further researches.