The Role of Neck Dissection in the Treatment of Supraglottic Laryngeal Cancer

Abstract

Much discussion of supraglottic cancer centers on management of the primary tumor. Radiation treatment, conservation surgery and transoral laser surgery have been employed with success according to the skills and preferences of the therapist and the nature of the primary tumor. The absence of prospective clinical trials has provided a basis for dispute concerning the most effective treatment for tumors at any given stage. Comparison of survival rates between different treatment modalities is dife cult because of a tendency to select patients with favorable primary tumors for surgical treatment and those with favorable nodal status for radiation therapy. Control of the primary tumor is achieved in the majority of patients, as total laryngectomy is an effective procedure of last resort. Thus the choice of modality and procedure for primary tumor control impacts mainly on quality of life, rather than survival. Survival of patients with supraglottic carcinoma is largely determined by the high rate of cervical node metastases (1‐3). Nodal status has a greater ine uence on the curability of supraglottic cancer than the status of the primary tumor, as histologically identie ed regional metastases are associated with signie cantly increased risk of distant recurrence and decreased survival (4). Neck disease reduces survival by about 50%. Cervical failures often occur in the undissected neck. The proper management of the neck in patients with supraglottic cancer remains a subject of much debate. Cervical metastases are clinically apparent in : 40% of patients with supraglottic cancer when e rst seen, and 50% of neck dissection specimens are histologically positive (5‐10). The efe cacy of treatment depends on the likelihood of regional tumor control and the morbidity resulting from treatment. Improved regional control should, in theory, result in an increase in survival and a reduction in morbidity. Determination of optimal treatment may be based on pathological studies of the incidence and distribution of metastases within the cervical nodes and on clinical studies of the effectiveness of different treatment strategies for cancer control and functional outcome. PATHOLOGIC STUDIES Pre◊alence of nodal metastases There may be considerable variation in the way different studies classify supraglottic cancer. Some include tumors that extend to the glottis, while some class these as transglottic (11) or multiregional (10). Most are also likely to include tumors with hypopharyngeal extension. The majority of advanced laryngeal cancers that are considered for neck dissection extend to the supraglottic larynx. Treatment of the neck in these cases should be the same as for supraglottic cancer. The overall prevalence of occult metastases for all laryngeal cancers is 24% (92.4%) (5‐8, 10‐15). Thirty-nine (93.5%) percent of patients with supraglottic cancer have nodal metastases at presentation and 49% (93.7%) of neck dissections are histologically positive (5‐7, 9, 10). Pattern of metastasis Most supraglottic tumors metastasize to levels II, III and IV. The distribution of metastases in pathologically positive necks, determined from combined studies, is 31% (28.3‐33.7%) to level II, 27% (24‐29.2%) to level III and 12% (10.3‐14.1%) to level IV. The risk of metastases to either level I or level V is very low at 2.4% (1.5‐3.3%) and 2.6% (1.7‐3.5%), respectively (4, 7, 8, 10‐13, 15‐17). There is no doubt that some tumors do metastasize to level V. Kowalski et al. (18) observed that levels I and V were rarely involved, and always in association with clinical and histologic involvement of levels II, III and:or IV.