Does blue dye contribute to success of sentinel node mapping for breast cancer?

We sought to evaluate the utilization of blue dye in addition to radioisotope and its relative contribution to sentinel lymph node (SLN) mapping at a high-volume institution.

Using a prospectively maintained database, 3,402 breast cancer patients undergoing SLN mapping between 2002 and 2006 were identified. Trends in utilization of blue dye and results of SLN mapping were assessed through retrospective review. Statistical analysis was performed with Student t test and chi-square analysis.

2,049 (60.2%) patients underwent mapping with dual technique, and 1,353 (39.8%) with radioisotope only. Blue dye use decreased gradually over time (69.8% in 2002 to 48.3% in 2006, p < 0.0001). Blue dye was used significantly more frequently in patients with lower axillary counts, higher body mass index (BMI), African-American race, and higher T stage, and in patients not undergoing skin-sparing mastectomy. There was no difference in SLN identification rates between patients who had dual technique versus radiocolloid alone (both 98.4%). Four (0.8%) of 496 patients who had dual mapping and a positive SLN had a blue but not hot node as the only involved SLN. None of these four had significant counts detected in the axilla intraoperatively. Nine (0.4%) of 2,049 patients who had dual mapping had allergic reactions attributed to blue dye.

Blue dye use has decreased with increasing institutional experience with SLN mapping. In patients with adequate radioactive counts in the axilla, blue dye is unlikely to improve the success of sentinel node mapping.