Safety and technical success of methylene blue dye for lymphatic mapping in breast cancer

Background We aimed to evaluate the safety and efficacy of methylene blue dye (MBD) for sentinel lymph node (SLN) mapping in breast cancer. Methods A total of 398 patients undergoing 401 SLN biopsy procedures with MBD were retrospectively reviewed and divided into 3 groups based on dye concentration and location of dye injection. Technical success and complication rates were compared. Results Overall technical success of SLN biopsy was 99.7%. Technical success of SLN mapping with MBD was lowest in the group receiving full strength dye in a peritumoral location (74%) and highest in the group that received very dilute MBD (1.25 mg/mL) in the subareolar location (92%, P = .004). The complication rate was highest in the first group (21%) and lowest in the latter (2%, P = .0003). Conclusions Dilute MBD (1.25 mg/mL) successfully maps SLNs with very few complications.