PET/CT in breast cancer staging is useful for evaluation of axillary lymph node and distant metastases

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.

We assessed, among patients with newly diagnosed primary breast cancer, associations of [¹⁸F] fluorodeoxyglucose (FDG) uptake (maximum standardized uptake value [SUV_max]) with clinical variables of the primary tumor, including regional nodal status and the presence of distant metastases.

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 SUV_max 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%).

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.