Conversion from Selective to Comprehensive Neck Dissection: Is It Necessary for Occult Nodal Metastasis? 5-Year Observational Study

OBJECTIVES: To compare the therapeutic results between selective neck dissection (SND) and conversion modified radical neck dissection (MRND) for the occult nodal metastasis cases in head and neck squamous cell carcinoma. METHODS: Forty-four cases with occult nodal metastasis were enrolled in this observational cohort study. For twenty-nine cases, SNDs were done and for fifteen cases, as metastatic nodes were found in the operative field, conversion from selective to MRNDs type II were done. Baseline data on primary site, T and N stage, extent of SND, extracapsular spread of occult metastatic node and type of postoperative adjuvant therapy were obtained. We compared locoregional control rate, overall survival rate and disease specific survival rate between two groups. RESULTS: Among the 29 patients who underwent SND, only one patient had a nodal recurrence which occurred in the contralateral undissected neck. On the other hand, among the 15 patients who underwent conversion MRND, two patients had nodal recurrences which occurred in previously undissected neck. According to the Kaplan Meier survival curve, there was no statistically significant difference for locoregional control rate, overall survival rate and disease specific survival rate between two groups (P=0.2719, P=0.7596, and P=0.2405, respectively). CONCLUSION: SND is enough to treat occult nodal metastasis in head and neck squamous cell carcinoma and it is not necessary to convert from SND to comprehensive neck dissection.