Single-Photon Emission Computed Tomography/Computed Tomographyfor Sentinel Node Mapping in Breast Cancer

Abstract

Accurate lymph node staging is essential for the prognosis and treatment in patients with cancer. The sentinel lymph node is the first node to which lymphatic drainage and metastasis from the primary tumor occurs. In malignant melanoma and breast cancer, the sentinel lymph node detection and biopsy already have been implemented into clinical practice. Currently, 2 techniques are used to identify the sentinel lymph nodes: technetium-99m-labeled colloid and blue dye. After peritumoral injection, the material migrates through the lymphatics to the first lymph nodes draining the tumor. The precise anatomic localization of the sentinel lymph nodes is important for minimal invasive surgery and to avoid incomplete removal of the sentinel lymph nodes. All sentinel lymph nodes should be resected to achieve a complete nodal staging. In the inguinal or low-axillary nodal stations, planar scintigraphic images mostly are adequate for the localization of the sentinel lymph nodes. However, in the regions of the head and neck, the chest, and the pelvis, an imaging method for the more precise anatomic localization of the sentinel lymph nodes preoperatively is highly desired. Recently, integrated single-photon emission computed tomography and computed tomography (SPECT/CT) scanners have become available. Initial reports suggest that integrated SPECT/CT might have an additional value in sentinel lymph node scintigraphy in head and neck tumors and tumors draining to the pelvic lymph nodes. We evaluated the clinical use of integrated SPECT/CT in the identification of the sentinel lymph nodes in patients with operable breast cancer. In our experience, localization and identification of sentinel lymph nodes was more accurate by integrated SPECT/CT imaging in comparison with planar images and SPECT images, respectively. In this report, the experiences of sentinel lymph node imaging with SPECT/CT are summarized.