Use of methylene blue in axillary sentinel lymph node biopsy in limited resource settings: A narrative review

Background: Sentinel lymph node biopsy (SLNB) is a standard technique for axillary staging in early breast cancer with clinically node-negative axillae. Radioactive tracer or Isosulfan Blue are the accepted methods of detecting sentinel nodes. Methylene blue (MB) dye has emerged as an accessible and cost-effective alternative to radioisotope tracers, particularly in low- and middle-income countries (LMICs).
Objectives: To review the use of MB and assess its efficacy, diagnostic accuracy, safety, and practical considerations in SLNB, particularly in LMIC settings. As a secondary objective, to compare the efficacy of MB with other tracer dyes.
Methods: A literature review was conducted using PubMed and Google Scholar databases. Studies evaluating MB in SLNB, published between 2000 and 2024, were included. Key outcomes included identification rate, false-negative rate (FNR), and adverse events. Data were synthesized narratively and tabulated.
Results and discussion: Among 16 eligible studies, MB demonstrated identification rates between 78 to 98%, with FNRs ranging from 3 to 10%. MB was shown to be safe, with minor adverse effects including dermal tattooing and rare allergic reactions. Its low cost and ease of availability make it more suitable for use in LMICs.
Conclusion: MB is a viable and effective tracer for SLNB in breast cancer, especially in resource-constrained settings. Adoption into local protocols and further comparative studies are recommended.