Sentinel Lymph Node Biopsy Using a Single-Dye Technique in a Cancer Center of North-East India: Cancer Epidemiology, Screening and diagnosis.

Sentinel lymph node (SLN) is the first node to receive the drainage directly from a tumor. SLN biopsy can be done in lieu of a formal lymphadenectomy in selected clinically node-negative cancers and minimizes morbidity compared with the latter. This prospective study was done in patients with operable clinically node-negative breast cancer, penile cancer, and malignant melanoma of extremities in a cancer center of North-east India from January 2019 to December 2019. All the patients underwent formal lymph nodal dissection after the SLN biopsy. Besides intraoperative frozen section study of the sentinel node(s), all the specimens, including the sentinel node(s), were subjected to paraffin section histopathology. SLN was identified successfully in 96% of patients. Mean number of sentinel node(s) dissected was 2.3. Study of SLN biopsy with methylene blue dye for staging was done with 100% sensitivity and 95.3% specificity. The SLN procedure was able to negatively predict the drainage nodal basin in 100% with an overall accuracy of staging of 96.5%. The true-positive rate noted was 88.8%, and the false-positive rate was 4.6%. SLN using a single-dye technique reliably identifies a sentinel node. This procedure can be safely adopted in patients with node-negative cancers as mentioned above to pathologically study the drainage basin.