Sentinel lymph node biopsy mapped with methylene blue dye alone in patients with breast cancer: A systematic review and meta-analysis

Background: Methylene blue dye is easy to obtain in developing countries and can be used in sentinel lymph node mapping for breast cancer. However, the accuracy of methylene blue alone for sentinel lymph node mapping in breast cancer has not been well defined. In this study, we collected data to assess the feasibility and accuracy of sentinel lymph node biopsy mapped with methylene blue alone in patients with breast cancer. Methods: We searched the PubMed, EMBASE, and Cochrane Library databases from January 1, 1993, to March 31, 2018. Selected studies had to have a defined group of patients with breast cancer in which MBD alone was used as the mapping technique for SNB. Results: 18 studies were included in this study. The combined identification rate was 91% [95% confidence interval (CI): 88%-94%, I2 = 68.3%], and the false negative rate was 13% (95% CI: 9%-18%, I2 = 36.7%). The pooled sensitivity, negative predictive value, and accuracy rate were 87% (95% CI: 82%-91%, I2 = 37.5%), 91% (95% CI: 87%-93%, I2 = 32.4%) and 94% (95% CI: 92%-96%, I2 = 29%), respectively. Conclusions: This meta-analysis found that mapping sentinel lymph node locations with methylene blue dye alone results in an acceptable identification rate but an excessive false negative rate according to the American Society of Breast Surgeons’ recommendations. Caution is warranted when using methylene blue dye alone as the mapping method for sentinel lymph node biopsy.