Sentinel node localization in breast cancer using intradermal dye injection: results, influencing factors and learning curve.

To evaluate the identification rate, false negative rate, concordance, negative predictive value of sentinel node localization in breast cancer using intradermal isosulfan blue injection whether this is accurate enough for surgical approach in breast cancer surgery and whether there is a significant learning curve for this technique. Factors affecting the outcomes of the procedure are also determined. From August 2002 to September 2003, 66 cases of stage 0-IIIB operable breast cancer patients underwent sentinel lymph node biopsy before standard breast cancer operation. Overall, identification rate was 80.3%, false negative rate was 10.6%, concordance was 86.8%, negative predictive value was 83.3%, sentinel node was the only node that was positive in 45.5%, and mean operative time was 55.1 minutes. Factors found to lower sentinel node identification rate are neoadjuvant chemotherapy and large tumor (T3-4) while previous excision was not found to affect the identification rate. There is significant learning curve in this technique and this should be performed at least 40-45 cases in the learning phase to accomplish a high identification rate and lower false negative rate before implicating into clinical practice.