PET/CT in breast cancer staging is useful for evaluation of axillary lymph node and distant metastases. (September 2021) - Davidson, Tima
Abstract: Introduction: Breast cancer outcome is dependent on disease stage. The aim of the study was to assess the role of PET/CT in the evaluation of axillary lymph node and distant metastases in women with newly diagnosed primary breast cancer. Materials and methods: We assessed, among patients with newly diagnosed primary breast cancer, associations of [ 18 F] fluorodeoxyglucose (FDG) uptake (maximum standardized uptake value [SUVmax ]) with clinical variables of the primary tumor, including regional nodal status and the presence of distant metastases. Results: Of 324 patients, 265 (81.8%) had focal uptake of FDG that corresponded with the cancerous lesion, and 21 (6.5%) had no FDG-avid findings. The remaining 38 patients had diffuse or nonspecific uptake of FDG. Among patients with a focal uptake of FDG (n = 265), the mean tumor size was 2.6 ± 1.9 (range 0.5–13.5), and the mean SUVmax was 5.3 ± 4.9 (range 1.2–25.0). In 83 patients (25.6%), PET/CT demonstrated additional suspected foci in the same breast. FDG-avid lymphadenopathy was observed in 156 patients (48.1%). Further assessment of lymph node involvement was available for 55/156 patients (axillary lymph node dissection [n = 21]; core needle biopsy [n = 34]) and confirmed axillary lymph node metastases in 47 (85.5%)). Thirteen patients (4.0%) had FDG-avid supraclavicular lymph nodes and six (1.9%) had FDG-avid internal mammary lymph nodes. Distant FDG-avid lesions were detected in 33 patients (10.2%). Conclusion: PET/CT is a useful diagnostic tool for staging breast cancer patients, but its use should be limited to specific clinical situations; further evaluation is needed. Highlights: FDG uptake significantly correlates with breast tumor size and grade. When findings are positive, PET/CT is very useful in detecting axillary metastases. A PET/CT scan negative for axillary lymph node metastases should not omit a biopsy. PET/CT showed a significant rate of distant metastases in breast cancer staging.