Breast lymphoscintigraphy for sentinel node identification in clinically axillary node negative breast cancer: A preliminary report of 35 cases

Full text: Lymphoscintigraphy is a sensitive, minimally invasive method for identifying sentinel lymph node (SLN). It has been extensively validated in malignant melanoma, penile cancer and recently in breast cancer. The aims of this study were to analyze and determine the clinical value of lymphoscintigraphy in SLN localization in woman undergoing surgery for breast cancer and to evaluate the predictive value of SLN versus axillary lymph node status in these patients. Pre-operative breast lymphoscintigraphy were preformed in 35 female patients with breast cancer and clinically negative axillary node. Mean age was 52.8 years (range 38 to 73 years). Prior to surgery, 74 MBq of Tc-99m nanocolloid in 0.2 to 0.5 ml was injected intra-dermally over the tumor mass. Immediately after injection, anterior dynamic images were acquired for 20 minutes, followed by anterior and lateral views static images at 30 minute, 1 hour and 2 hour using single-head gamma camera until SLN visualized. The SLN location was marked externally on skin. All patients underwent standard modified radical mastectomy with axillary node dissection. All lymph nodes were examined carefully by a skilled histopathologist. SLNs were assessed by visual inspection of both dynamic and static images. Comparison of SLN and axillary lymph node histopathologic results was done in order to define the means of SLN biopsy's ability to reflect the final status of axilla. The mean size of the primary breast tumor mass was 2.54 cm (1.0 to 4.0 cm). In 20/35 (57.1%), the SLNs were visualized in 20-minute dynamic imaging. In 12 patients, the SLNs were seen after delayed imaging and/or repositioning the patient. Overall estimated SLN identification rate was 91.43%. Of those 32 cases in whom the SLNs were localized on lymphoscintigraphy, 9 cases were positive for metastatic tumors and the rest were negative for tumor involvement. Four out of these 9 cases, SLN was the only node that contained metastatic tumor cells and in 5 cases, additional concomitant axillary lymph nodes metastases were detected. In 4 cases, SLN was negative on frozen section and skipped metastasis lymph nodes were noted. Of those 3 cases that the SLNs were unable to localize on lymphoscintigraphy, the axillary lymph nodes were found positive for tumor cells in 2 cases and the remaining 1 case was negative for tumor involvement. We conclude that SLN localization using lymphoscintigraphy is an accurate, minimally invasive procedure for staging breast cancer patients with clinically negative axillary lymph node status and can substantially reduce the morbidity and costs of surgical treatment by avoiding unnecessary axillary lymph node dissection in the majority of patients. (author)