The predictive value of methylene blue dye as a single technique in breast cancer sentinel node biopsy: a study from Dharmais Cancer Hospital.

Background: Axillary lymph node dissection (ALND) has been the standard treatment of breast cancer axillary staging in Indonesia. The limited facilities of radioisotope tracer and isosulfan or patent blue dye (PBD) have been the major obstacles to perform sentinel node biopsy (SNB) in our country. We studied the application of 1% methylene blue dye (MBD) alone for SNB to overcome the problem.

Methods: This prospective study enrolled 108 patients with suspicious malignant lesions or breast cancer stages I-III. SNB was performed using 2-5 cc of 1% MBD and proceeded with ALND. The histopathology results of sentinel nodes (SNs) were compared with axillary lymph nodes (ALNs) for diagnostic value assessments.

Results: There were 96 patients with invasive carcinoma from July 2012 to September 2014 who were included in the final analysis. The median age was 50 (25-69) years, and the median pathological tumor size was 3 cm (1-10). Identification rate of SNs was 91.7%, and the median number of the identified SNs was 2 (1-8). Sentinel node metastasis was found in 53.4% cases and 89.4% of them were macrometastases. The negative predictive value (NPV) of SNs to predict axillary metastasis was 90% (95% CI, 81-99%). There were no anaphylactic reactions, but we found 2 cases with skin necrosis.

Conclusions: The application of 1% MBD as a single technique in breast cancer SNB has favorable identification rates and predictive values. It can be used for axillary staging, but nevertheless the technique should be applied with attention to the tumor size and grade to avoid false negative results.