Significance of an Intraoperative Frozen Section of the Axillary Sentinel Lymph Node and the Preoperative PET Evaluation of Breast Cancer Patients

Yang, Jung Hyun; Lee, Tae Seung; Lee, Hae Kyung; Jung, Sung Hoo; Nam, Seok Jin; Lee, Byung Boong; Kim, Byung Tae

Abstract

The axillary lymph node status is the most important prognostic factor when deciding whether or not to treat breast cancer patients with adjuvant therapy and its status is determined by radical axillary lymph node dissection. Although radical axillary dissection is regarded as the gold standard for staging breast cancer, postoperative problems, such as lymphedema are considerable. However the same procedure is performed on all patients even in patients with no sign of axillary lymph node involvement. Recently, many trials that intend to determine the axillary status through more conservative procedures have been reported. This study was undertaken to evaluate the diagnostic accuracy of preoperative positron emission tomography (PET) and sentinel lymphadenectomy (SLND) for the detection of axillary lymph node metastases in patients with breast cancer. The sentinel node was studied with vital dye, isosulphan blue, to see if the sentinel node could predict axillary nodal status with accuracy. Eighteen patients (14 cases of radical mastectomy, 4 cases of conserving surgery) with breast cancer underwent axillary dissection, who had a preoperative PET and a successful intraoperative SLND for staging in the Department of Surgery at Samsung Medical Center from September 1995 to August 1996. PET imaging with the radiolabeled glucose analogue (F-18 FDG) was used to visualize the primary breast tumors. Sentinel lymphadenectomy was done under general anesthesia, and isosulphan blue was injected into the center of the mass and its margin. Axillary dissection was performed to identify any stained lymphatics. If stained lymphatics were identified, the dissection was extended along the lymphatics bidirectionally to detectthe stained lymph node nearest to the primary tumor (sentinel node). After frozen biopsy of the sentinel node, a routine axillary lymph node dissection was performed. Following this, the pathologic results of both specimens were compared. Out of all 18 cases, 6 cases had the sentinel node as the only positive node in the permanent pathologic results. Although the preliminary lymph node results were not positive in 3 patients who had undergone PET and in one patient who had undergone a frozen biopsy of the sentinel node, their actual permanent axillary nodes were later found to be positive. The sensitivity and the specificity of the sentinel node method and the PET method for detection of axillary lymph node metastases were 83% and 100% and 50% and 100%, respectively. A sentinel lymphadenectomy with multiple sectioning and immunohistochemical staining of the sentinel nodes increases the accuracy of axillary staging in breast cancer and can identify significantly more patients with 1ymph node metastases, especially micrometastases. The sentinel node method (SLND) can accurately predict the axillary nodal status in breast cancer patients. Therefore, a more conservative procedure can be performed on patients with negative sentinel node status, and routine axillary dissection can be omittend when possible in the future.