Researchers have found that fibroblast activation protein inhibitor (FAPI) positron-emission tomography/computed tomography (PET/CT) may offer more accurate staging in patients with newly diagnosed breast cancer than fluorine (F)-18–labeled fluorodeoxyglucose (FDG) PET/CT, according to new findings presented by Hao et al at the 2024 Society of Nuclear Medicine and Molecular Imaging (SNMMI) Annual Meeting (Abstract 242411).
Background
Although F-18–FDG PET/CT is commonly used in breast cancer staging, the approach often has limitations such as false positives in inflammatory breast lesions and reduced sensitivity in specific breast cancer subtypes. Previous small-sample, retrospective studies have indicated that gallium (Ga)-68–FAPI may outperform F-18–FDG PET/CT with its high sensitivity in the detection of primary tumors and metastases among patients with breast cancer.
“There is currently a lack of evidence on the efficacy of FAPI PET/CT, especially in large sample cohorts. Our study sought to add to the literature by assessing FAPI PET/CT for the systemic staging of newly diagnosed breast cancer compared with F-18–FDG PET/CT,” emphasized lead study author Zhixin Hao, MD, a nuclear medicine physician at Peking Union Medical College Hospital in Beijing, China.
Study Methods and Results
In the new study, the researchers assigned 121 patients with newly diagnosed breast cancer who underwent F-18–FDG imaging to receive either Ga-68–FAPI-04 PET/CT (n = 53) or A1F-18–FAPI-04 PET/CT (n = 68). The lesions were recorded as positive if their uptake exceeded that of the adjacent background tissue. The TNM clinical stages were determined by F-18–FDG and FAPI PET/CT, according to the American Joint Committee on Cancer Staging Manual.
Compared with the clinical TNM stage determined by F-18–FDG PET/CT, The researchers found that nearly 19.8% of the patients were restaged by FAPI PET/CT—representing the potential benefits of the radiotracer in clinical practice. Further, management plans were optimized in six of the patients as a result of the additional detection of bone lesions and internal mammary lymph nodes.
Notably, FAPI PET/CT upstaged 21.7% of patients diagnosed with stage IIA breast cancer by F-18–FDG PET/CT. The researchers emphasized that those with stage IIA disease should be considered for systemic staging with FAPI PET/CT at the time of initial diagnosis.
Conclusions
“This study is significant as it has the potential to advance personalized treatment strategies for [patients with] breast cancer patients. FAPI PET/CT for the initial staging of breast cancer has the potential to reduce unnecessary treatments and improve patient outcomes,” concluded Dr. Hao.
Disclosure: For full disclosures of the study authors, visit xcdsystem.com.
