Prospective comparison of peritumoral and subareolar injection of blue dye alone, for identification of sentinel lymph nodes in patients with early stage breast cancer

Abstract

Background and objectives: Various techniques are used for the identification of the sentinel node (SLN). We prospectively compare the efficacy of SLN biopsy and the number of SLNs identified, by injecting methylene blue (MB) alone in the subareolar area (SA) or peritumorally (PT) in patients with early stage breast cancer.

Methods: Patients were randomized in two groups (SA or PT injection). A linear regression model was used to estimate the effect of various parameters on the identification rate and on the number of SLNs retrieved.

Results: At least one SLN was identified in 61 of 66 (92.4%) procedures in the SA group and in 57 of 60 (95%) procedures in the PT group (P = 0.55). The mean number of SLNs removed with the SA injection method was 1.64 ± 0.6 nodes compared with 2.23 ± 0.7 nodes identified with the PT injection (range: 1-4, P < 0.001). The injection site was the only factor affecting the number of SLNs retrieved.

Conclusion: The use of MB alone is an efficient method for identification of the SLN. The PT injection route yields a higher number of SLNs than the SA route, comparable with the number of SLNs retrieved, when combined tracing agents and multiple injection sites are used.