Background: This study examined whether the volume of isosulfan blue dye used in sentinel lymph node (SLN) mapping in breast cancer is related to the SLN identification rate or to the incidence of allergic reactions.
Methods: From January 2001 to November 2002, 1728 breast cancer patients underwent 1832 SLN mapping procedures with the combined technique of intraparenchymal blue dye and intradermal radioisotope. Details of each procedure and all allergic reactions were prospectively recorded. Bilateral synchronous SLN procedures were considered as one dye exposure but as two distinct procedures for determining mapping success. Dye-only success was defined as the proportion of cases in which the SLN was identified by blue dye alone. Overall dye success was defined as the proportion of cases in which the SLN was identified by blue dye with or without isotope.
Results: When stratified by volume of blue dye, there were no significant differences in dye-only successes, overall dye successes, or mapping failures. Allergic reactions were documented in 31 (1.8%) of 1728 patients. Hypotensive reactions occurred in 3 (.2%) of 1728 patients; 2 (.1%) required pressor support. There was a nonsignificant trend toward fewer allergic reactions with smaller volumes of blue dye.
Conclusions: In combined-technique SLN mapping protocols for breast cancer, using smaller volumes of blue dye may represent a means of optimizing the safety of the procedure without compromising its success.