Combined Methylene Blue Dye and Radioactive Tracer Technique for Sentinel Lymph Node Localization in Early Breast Cancer

Background: Sentinel lymph node biopsy is a technique used to identify the axillary node most likely to contain tumor cells that have metastasized from a primary carcinoma of the breast. This technique provides accurate staging with fewer complications than axillary dissection and may result in decreased costs. We designed the present study to determine the accuracy and success rate of a combined blue dye and radioactive tracer technique in sentinel node localization. Methods: This prospective study included 70 patients with early stage (tumor > 5 cm; T1, T2) operable breast cancer and nonpalpable axillary lymphadenopathy seen between 2005 and 2009. Patients underwent sentinel lymph node localization using 4 mL of blue dye combined with radioactive colloid. After identification and removal of the sentinel node(s), the axilla was checked for any residual radioactivity. A sentinel node was defined as any node that was hot, hot and blue or only blue. Results:The sentinel node was identified in 66 patients with a detection rate of 94.2%, and a mean of 1.5 sentinel nodes were identified and harvested (range of 1-4). In 23 cases, the sentinel lymph node contained metastatic disease on pathological assessment. There was no pathological evidence of any metastases in the sentinel node in the remaining 43 patients. All sentinel lymph nodes were located in level I of the axillary region. In four patients, no sentinel lymph node was found, so axillary dissection was performed. The sensitivity of the procedure in predicting further axillary disease was 95.6% with a specificity of 97.6%. Conclusion: The present study describes the blue dye and radioisotope localization technique as successful in identifying the sentinel lymph node in early-stage breast cancer patients.