III Frontier of accurate diagnosis of breast cancer. 1. Present state and prospect of preoperative diagnosis of progression, differential diagnosis of benign and malign natures, and efficacy evaluation of neoadjuvant chemotherapy. 2) Clinical efficacy and problem of FDG-PET (PET/CT) in breast cancer

On authors' experience and literature, clinical efficacy and limitation of fluorodeoxyglucose-positron emission tomography (FDG-PET) (PET/CT) in the breast cancer are described and discussed for detection of the primary lesion, preoperative staging and lymph node diagnosis, diagnosis of recurrence and remote metastasis, evaluation of therapeutic efficacy, and prediction of prognosis. For routine breast cancer screening, authors think PET/CT is not always effective because of many false positive/negative findings. PET/CT and subsequent CT with iodine contrast media are thought to be useful for preoperative staging and planning in conservative surgery though detection of micro-metastatic nodes are often difficult. PET is reportedly superior to 99mTc-MDP scintigraphy in bone metastasis detection, but which conceivably depends on the nature (osteogenic/osteolytic) of the lesion. For recurrence and remote metastasis, the diagnostic sensitivity, specificity and accuracy of PET/CT are reported to be as high as 84-98, 84-94 and 86-97%, respectively. Standardization of PET/CT monitoring is now necessary to evaluate the therapeutic efficacy. SUV which indicates the degree of FDG accumulation in the lesion, can be used for prediction of prognosis in future. Awaited is the development of more effective PET/CT apparatus and agent (instead of FDG) for detection of small metastatic lesions, axillary lymphatic metastasis, and viable focus after therapeutic treatments. (R.T.)