The role of positron emission tomographic imaging in breast cancer.

Studies have shown that deoxy-2-fluorodeoxyglucose ((18)FDG) positron emission tomography (PET) has limited value in detecting primary tumors and axillary lymph node involvement in breast cancer. PET is most successful when it is used to evaluate locally advanced breast tumors. Identification of smaller, earlier-stage tumors and noninvasive or lobular tumors has been suboptimal. Because of several factors, PET should not replace standard techniques for evaluation of breast cancer, especially for micrometastasis. However, PET can provide invaluable information about disease extent, recurrent disease, and distant metastases, and this information can affect treatment decisions. (18)FDG PET can also facilitate the differentiation of therapy responders from nonresponders, allowing treatment regimen changes at an earlier stage.