The application of methylene blue coloration technique in axillary lymph node dissection of breast cancer.

Background: To analyze the associated factors that affect the coloration of methylene blue (MB) in axillary lymph node dissection (ALND) of patients with breast cancer and to explore the tracer effect of MB in high axillary lymph node metastasis, to guide surgical treatment.

Methods: We recruited 170 patients who underwent ALND, all of them were injected MB before operation. We analyzed the relationships between the clinical factors of age, body mass index (BMI), molecular typing, TNM staging, neoadjuvant chemotherapy, injection time and position and the MB coloration by univariate and multivariate analyses. A total of 84 cases were selected for observation of the application value of MB during intervention involving the lymph nodes upper axillary vein.

Results: Of 170 cases, 138 cases (81.17%) were colored. Univariate analysis showed that significant differences were observed between differing BMI's (χ=24.074, P<0.0001) and injection times (χ=41.207, P<0.0001). Multivariate analysis showed that injection time (P=0.016) was the clinical factor associated with MB coloration. More than 60 minutes before surgery and MB injection, the possibility of methylene blue colored was 0.088 times higher than 10 minutes (P=0.010, 95% CI, 0.014, 0.554). MB was used to track the lymph node upper axillary vein with a sensitivity of 12.5%, a specificity of 100%, a false negative rate of 87.50%, and a false positive rate of 0; the kappa coefficient was 0.051 (χ=0.679, P=0.404).

Conclusions: Among the clinical factors, MB coloration was worse more than 60 minutes before ALND. Using the technology of MB color, lymph nodes can be clearly identified. It has great guiding value for the doctors who learn the operation initially. However, it is still prudent to use MB for high lymph node dissection.