Assessment of the efficacy and oncological safety of sentinel lymph node biopsy in node-negative breast cancer using methylene blue dye

Background
Sentinel lymph node (SLN) biopsy in patients with breast cancer with clinically negative axillary nodes is an innovative technique in the management of the axilla. SLN biopsy has been performed using different techniques including injection of patent blue dye, radioactive colloid, and recently methylene blue dye. The aim of this study was to assess the safety and efficacy of methylene blue dye as a mapping agent for SLN biopsy in clinically axillary node-negative breast carcinoma.
Patients and methods
Between January 2014 and October 2016, 50 female patients with established diagnosis of breast carcinoma by tru-cut biopsy and clinically negative ipsilateral axillary lymph nodes were included in the study. All the patients were operated upon in Ain Shams University hospitals. After induction of anesthesia, 3–5 ml of sterile 1% methylene blue was infiltrated into the subareolar tissue on the affected side. The lymph nodes receiving the blue dye were excised as the SLN. Excised specimen with the axillary tissue was sent for histopathological examination. The presence or absence of metastasis in SLN and axillary lymph nodes was compared. Statistical analysis was carried out to know sensitivity, specificity, and accuracy of SLN biopsy in breast cancer.
Results
The incidence of breast cancer was highest at 41–50 years. Of our 50 cases, SLN was identified in 44 cases using methylene blue dye. The identification rate was 88%. None of the patients had negative SLN but positive axillary lymph nodes (false negative), and in six cases, SLNs were involved only but not the rest of the axilla (false positive). The sensitivity, specificity, positive predictive value, and negative predictive value were 100, 85.7, 25, and 100%, respectively.
Conclusion
This study confirms the safety and efficacy of methylene blue dye as a mapping agent for SLN biopsy in axillary node-negative breast cancer.