Detection of locoregional and distant recurrences in breast cancer patients by using FDG PET

Cases of recurrence of breast cancer can pose considerable diagnostic and therapeutic challenges for the oncologic team. The prognosis and management decisions are based on knowledge of the true extent of disease. Conventional staging methods, including physical examination, assessment of levels of tumor markers, cross-sectional imaging, and bone scintigraphy, may not reliably demonstrate the extent of disease in all cases. Physical examination and cross-sectional imaging (computed tomography [CT] or magnetic resonance imaging) can be problematic because (a) the sequelae of previous surgery and radiation therapy can be difficult to distinguish from recurrent neoplasms and (b) early metastatic disease (small lesions) can be difficult to distinguish from benign lesions that are too small to characterize. Positron emission tomography (PET) with 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG) can help clarify inconclusive findings from physical examination and cross-sectional imaging. FDG PET is more sensitive than CT in detection of lymphatic spread of disease to locoregional and mediastinal nodes. Metastases at distant sites including the lung, bone, and the liver are also readily detected at FDG PET. FDG PET has been proved accurate in restaging cases of recurrent breast cancer and will likely aid in directing therapy in these cases.