Relieving the pain of sentinel lymph node biopsy tracer injection.

Sentinel lymph node biopsy (SLNB) has been reliably accurate as a minimally invasive surgical alternative for identifying lymphatic breast metastasis. During mapping, the injection of a radioactive tracer or isosulfan blue dye to differentiate the SLN is acutely painful. The use of the eutectic mixture of lidocaine and prilocaine (EMLA) cream to reduce tracer injection pain has been reported anecdotally. A retrospective study compared injection discomfort of 20 women who had undergone SLNB without EMLA and 20 women who had undergone SLNB with the EMLA protocol. Results indicated a significant difference in mean pain rating. Standards of care should include the use of EMLA prior to intradermal SLN tracer injection unless contraindicated.