A Prospective Cohort Study on Neck Lymph Node Mapping in Oral Cancers Using Methylene Blue Dye.

Area of Science:

• Oncology
• Surgical Pathology

Background:

• Management of the N0 neck in early-stage oral cancer remains controversial, often leading to overtreatment or undertreatment.
• Sentinel lymph node (SLN) biopsy offers a precise method to detect occult lymph node metastasis, guiding neck dissection decisions.

Purpose of the Study:

• To evaluate the feasibility and accuracy of sentinel lymph node (SLN) biopsy using methylene blue dye in node-negative oral squamous cell carcinoma.
• To assess the efficacy of methylene blue-assisted SLN biopsy in identifying occult metastases and guiding treatment decisions.

Main Methods:

• A prospective observational study involving operable oral squamous cell carcinoma patients with clinically and radiologically node-negative necks.
• Methylene blue dye was injected peritumorally to identify SLNs, followed by completion neck dissection.
• Analysis of SLN identification rates, metastatic status, and diagnostic accuracy metrics (sensitivity, specificity, NPV).

Main Results:

• SLN was identified in 82.98% of 47 patients, with 53.85% having more than two SLNs, commonly in levels IB, IA, and IIA.
• Occult metastasis was detected in 12.82% of cases, primarily in T2 tumors.
• Sensitivity, specificity, and negative predictive value (NPV) were 50%, 100%, and 88.89%, respectively.

Conclusions:

• Methylene blue-assisted SLN biopsy is feasible and accurate for oral cancer management.
• Methylene blue dye alone is insufficient for SLN identification in oral cavity cancer but can augment lymphoscintigraphy.
• Further multi-institutional trials are needed to refine the technique's applicability, especially in resource-limited settings.