Evaluation of sequential FDG-PET/CT for monitoring bone metastasis of breast cancer during therapy: correlation between morphological and metabolic changes with tumor markers

Purpose The purpose of this study was to clarify the significance of positron emission tomography (PET) and computed tomography (CT) findings for evaluating the bone metastasis of breast cancer during therapy. Patients and methods Forty-seven patients with bone metastases from breast cancer who underwent sequential FDG-PET/CT studies during therapy were enrolled. A total of 771 lesions were identified. The changes in the PET and CT findings were compared with the tumor marker levels in each patient by calculating the weighted kappa value. The correlation between the PET and CT findings was examined for each lesion by an adjusted Chi-square test. Results The change in the tumor marker levels was substantially correlated with the PET findings and moderately correlated with the CT findings (weighted kappa = 0.780 and 0.585 for quadratic weighting, respectively). An increase in FDG uptake was correlated with lytic changes on the CT images (62/65, 95.4 %, p