18F-FDG uptake by metastatic axillary lymph nodes on pretreatment PET/CT as a prognostic factor for recurrence in patients with invasive ductal breast cancer.

UNLABELLED This study assessed the maximum standardized uptake value of metastatic axillary lymph nodes in patients with invasive ductal breast cancer (IDC) to determine the pretreatment prognostic value of (18)F-FDG PET/CT for disease-free survival (DFS). METHODS Sixty-five female IDC patients who had undergone pretreatment (18)F-FDG PET/CT and had pathologically confirmed axillary lymph node involvement without distant metastasis were enrolled. All patients showed complete remission after first-line treatment. To obtain nodal SUVmax, a transaxial image representing the highest (18)F-FDG uptake was carefully selected and a region of interest was manually drawn on the (18)F-FDG-accumulating lesion. Clinicopathologic parameters such as age, TNM stage, estrogen receptor status, progesterone receptor status, human epidermal growth factor receptor 2 status, and primary-tumor and nodal SUVmax on PET were analyzed for their usefulness in predicting recurrence. Combinatorial effects and interactions between variables that were significant by univariate analysis were examined using multivariate Cox proportional-hazards models. RESULTS Twelve of 65 patients (18.5%) experienced recurrence during follow-up (median follow-up, 36 mo; range, 21-57 mo). Nodal SUVmax was significantly higher in patients with recurrence than in those who were disease-free (recurrence group: 5.2 ± 2.3, vs. disease-free group: 1.9 ± 1.9, P < 0.0001). A receiver-operating-characteristic curve demonstrated a nodal SUVmax of 2.8 (sensitivity, 91.7%; specificity, 86.8%; area under the curve, 0.890) to be the optimal cutoff for predicting DFS. Univariate analysis revealed that T stage, N stage, estrogen receptor status, and primary-tumor and nodal SUVmax correlated significantly with DFS. Among these 5 variables, only nodal SUVmax was found to be a single determinant of DFS by multivariate analysis (hazard ratio, 31.54; 95% confidence interval, 2.66-373.39; P = 0.0065). CONCLUSION Nodal SUVmax on pretreatment (18)F-FDG PET/CT may be an independent prognostic factor for disease recurrence in patients with IDC.