Intermediate Grade Salivary Gland Mucoepidermoid Carcinoma: Is Neck Dissection Indicated?

OBJECTIVE: NCCN guidelines recommend a neck dissection addressing at least levels II-IV for high-grade mucoepidermoid carcinoma (MEC) and close observation of the lymphatic basins for low-grade MEC. However, no guidelines exist for intermediate-grade MEC with clinically and radiologically uninvolved cervical lymph nodes. STUDY DESIGN: Retrospective analysis. SETTING: Patients with intermediate-grade MEC with a clinically N0 neck from our tertiary academic institution from 2015 to 2023. METHODS: Evaluation for histologic lymphatic metastases was performed when surgeons elected to perform neck dissection. For patients who did not receive a neck dissection, review of medical records to document the results of clinical observation, and specifically regional lymphatic recurrence, on long-term follow-up. RESULTS: Thirty-five patients with N0 intermediate grade MEC were included, composed of 26 patients who underwent primary tumor resection and neck dissection and 9 patients who received resection of the primary tumor without neck dissection. One out of 26 patients receiving neck dissection was found to have lymphatic metastasis. Watchful waiting of 9 patients demonstrated no recurrence at a mean follow up of 40 months. Thus, 1 out of 35 patients (2.9% [95% confidence interval: 2.7%-3.1%]) had documented metastatic disease in the lymphatics. CONCLUSIONS: For patients presenting with intermediate-grade MEC, there was a low chance (2.9%) of positive histologic or clinical lymphatic metastases in the neck. Given this low risk, we believe the potential benefit of neck dissection may be outweighed by the potential morbidity. Careful consideration of the clinical behavior of the lesion could be considered along with a more selective approach toward elective lymphadenectomy in intermediate-grade MEC.