Steroid Receptor Imaging in Breast Cancer.

A high proportion of breast cancers express estrogen and progesterone receptors. This can guide oncologists on hormonal therapy's suitability for breast cancer. With second-line hormonal therapy agents such as aromatase inhibitors and pure antagonists, imaging methods could be critical in assessing the presence of estrogen or progesterone receptors. Several radiopharmaceuticals were developed for imaging of estrogen or progesterone receptors. Estrogen receptor imaging could play a useful role in predicting the response of breast cancer to hormone therapy. Large-scale trials will determine the respective roles of tamoxifen, aromatase inhibitors, and fulvestrant, and the optimal drug administration sequence. Early noninvasive identification of patients who will likely fail all forms of hormonal therapy could be achieved by positron emission tomography.