Is dissection of level IV absolutely necessary in elective lateral neck dissection for clinically N0 laryngeal carcinoma?

A prospective study of 73 previous untreated consecutive patients with clinically N0 laryngeal squamous cell carcinoma (SCC) from January 1997 to October 2002 was undertaken to determine whether level IV lymph nodes can be saved in elective lateral neck dissection (LND) performed as a treatment for the N0 neck. The incidence of pathological metastases to level IV lymph nodes was evaluated, as were the incidence of regional recurrence after elective LND, and postoperative complications such as chylous leakage and phrenic nerve paralysis. A total of 142 LNDs were enrolled in this prospective study. The mean number of harvested lymph nodes by level was as follows; 13.1 in level II, 7.1 in level III, and 9.2 in level IV. Pathologic examination revealed nodal involvement in 25 neck specimens (17.6%, 25 of 142). Five necks had lymph nodes which were positive for microscopic metastasis in level IV (3.5%, 5 of 142). These necks were all ipsilateral (6.8%, 5 of 73) and none of the 69 contralateral neck specimens had level IV lymph node metastasis (0%, 0 of 69). With regard to T stage, 3.3% (1 of 30) of ipsilateral necks of T2 tumors exhibited occult metastasis in level IV lymph nodes, 5.9% (2 of 34) for T3 tumors, and 33.3% (2 of 6) for T4 tumors. There were no cases of T1 (n = 3). Separate skip metastasis in level IV lymph nodes was observed in two necks (1.4%, 2 of 142). Four cases of regional recurrence (5.5%, 4 of 73) were observed. Postoperative chylous leakage and phrenic nerve paralysis occurred in four cases (5.5%, 4 of 73) and two cases (2.7%, 2 of 73), respectively. The results of the present study demonstrate the rare incidence of level IV occult lymph node metastasis, as well as infrequent nodal recurrence after elective LND in the treatment of clinically N0 laryngeal SCC. Therefore, dissection of level IV lymph node pads, especially in the ipsilateral neck of early T staged tumors or the contralateral neck, may be unnecessary for the treatment of laryngeal SCC patients with a clinically N0 neck.