Introduction

Laryngeal and hypopharyngeal squamous cell carcinoma, the most common malignant neoplasm of the upper aerodigestive tract in adults, accounts for about 30–40% of all head and neck cancer and 1–2.5% of all human cancers [1,2,3]. Although many factors like clinical stage, site, size of the tumor, histologic grade and depth of invasion have been evaluated as potential prognostic indicators, none have proven to be reliable or to have any real clinical value. Cervical lymph node involvement in laryngeal and hypopharyngeal tumors has a marked impact on disease prognosis. Approximately 18% of patients with laryngeal cancer and 60% of patients with hypopharyngeal cancer had lymph node metastasis at the time of presentation. Cervical lymph node involvement in laryngeal and hypopharyngeal tumors has a marked impact on disease prognosis, and the management of regional lymph nodes is a crucial component of the overall treatment plan [4,5,6]. The characteristics of the cervical lymph node metastasis in laryngeal and hypopharyngeal carcinoma patients, the clinicopathological factors and the oncological outcome of neck metastasis in these patients were evaluated in our study. We also studied whether a lateral selective neck dissection is sufficient for the management of the neck metastasis in these tumors.

Materials and Methods

A retrospective analysis of all patients with squamous cell carcinoma of the larynx and hypopharynx who underwent laryngectomy or laryngopharyngectomy with unilateral or bilateral neck dissection between January 2006 and December 2010 was conducted. The American Joint Committee on Cancer Tumor-Node-Metastasis classification system was used to classify primary tumor of the neck, and the Memorial Sloan-Kettering Cancer Center classification was used to classify the cervical lymphatic chain [7, 8].

Clinicopathological factors including age, sex, clinical stage, sub site, size of the tumor, histologic grade, depth of invasion, perineural invasion, lymphovascular emboli, lymph node status and the levels of lymph nodes were evaluated. In the present series, selective neck dissection was done for all node-positive cases clearing levels II–V. For node-negative cases, a neck dissection was performed in supraglottic and hypopharyngeal cancer cases, those with extralaryngeal extension and also in salvage surgeries for T3 and T4 stages. The level and stage of cervical node involvement were correlated with the various clinical and pathological factors of the primary. The recurrence rate and the survival in these patients were analyzed by Cox regression model.

Results

The characteristics of the patients, the location of tumor and nature of surgery are given in Table 1. Forty-four (26%) patients were in the early T stage and 126 (74%) were in the late T stages at the time of surgery. Forty-eight (28%) patients had thyroid cartilage erosion and 27 (16%) patients had extralaryngeal spread of disease.

Table 1 Characteristics of the sample
Full size table

Clinical node positivity (cN+) was seen in 49 (28%) patients and pathological node positivity (pN+) was seen in 58 (34%) patients. According to our study, 42% of patients with supraglottic involvement, 61% of the patients with pyriform sinus involvement, 56% of patients with thyroid cartilage erosion and 88% of patients with base of tongue involvement had pathologically positive lymph node metastasis.

In patients with pathologically positive nodes, positive nodes were more commonly seen on the ipsilateral side of the neck. The pathological lymph nodes were seen predominantly in level II (28/58) (48%) and level III (24/58) (41%) regions (Fig. 1).

Fig. 1
figure 1

Distribution of neck node involvement among the sample

Full size image

The recurrence rate was also analyzed and it was found that 42 (25%) patients had either locoregional recurrence, distant metastasis or second primary. On the last follow-up, 124 (73%) patients were alive without any disease, 37 (22%) patients were alive with disease and 9 (5%) patients were dead. The recurrences and distant metastasis were significantly more in the node-positive cases. The disease-free survival among the node-negative and node-positive cases were 76 and 46%, respectively, and this difference was statistically significant (p = 0.01).

Sixty-six percent (n = 102) of the patients were pathologically N0, and on subset analysis, 46 were primary and 56 were salvage cases. Eighty-six percent (n = 88) of the patients with pN0 were having primary in the glottis, and all the 102 patients were alive with no disease during the last follow-up. Therefore, we conclude that other clinicopathological factors have no significant impact on disease-free survival and overall survival of patients with pathologically N0 status.

Discussion

Laryngeal and hypopharyngeal squamous cell carcinoma readily metastasizes to adjacent cervical lymph nodes and it is the most important prognostic factor. The presence of a single positive lymph node can reduce disease-free survival at 5 years by 50%. According to Esposito et al., 27% of the patients with supraglottic cancer have micrometastasis. His study revealed that 14% of the cases had metastatically involved lymph nodes in the T1 tumors, 21% in the T2 tumors, 35% in the T3 and 75% in the T4. The presence of occult neck metastasis seems to be related to the T stage, grade and extension across the midline of the tumor. This was true in our series also. We found more nodal disease in cases with extralaryngeal extension and base tongue involvement. Lymphatic metastasis was also more with supraglottic and pyriform sinus tumors as these sites have more lymphatic channels. Also, it was found to be more for high-grade tumors and for primary lesion with perineural invasion [8, 9] (Table 1).

Complete functional neck dissection removing levels I through V used to be the procedure of choice for addressing the neck nodes. However, the procedure was associated with injury to the spinal accessory nerve, deep cervical plexus and thoracic duct. Improved knowledge about the lymphatic channels and the lymphatic flow changed the radical approach to modified radical neck dissection and then to selective neck dissection. But, according to the findings of the Committee for Head and Neck Surgery and Oncology of the American Academy of Otolaryngology—Head and Neck Surgery, the dissection was limited to levels II, III and IV [10].

More recently, certain authors argued against dissecting levels IIb and IV in N0 tumor, to reduce associated morbidity (while others consider the occult lymph node metastasis rate at these levels to be non-negligible and it was 37% in Shah’s series [11]) and hence argue that functional dissection is the appropriate approach to prevent regional recurrence. So, in laryngeal and hypopharyngeal cancers, lateral neck dissection has recently become a preferred treatment method in the N0 and N1 neck. According to Mnejja et al., super selective neck dissection (IIa, III) is adequate in T1T2 N0 tumor. In case of advanced tumor or pre-epiglottic space or cartilage invasion, functional neck dissection is mandatory [12]. According to Ronald et al., selective upper node dissection and inspection during laryngectomy reduced the need for an elective neck dissection with its morbidity in the clinically N0 neck [14].

Isaac A. Bohannon et al. conducted a randomized controlled trial in clinically N0 patients with recurrent carcinoma of the larynx. They found that only 4% had positive nodal disease, but the complication rate was significantly higher with neck dissection than that for patients without neck dissection (42.2 vs 21.3%). Moreover, there was no survival advantage for patients with neck dissection compared to no neck dissection [13].

Lawson et al. proposed that sentinel node sampling is reliable in the staging of clinically N0 neck in patients with carcinoma supraglottis. The sentinel node sampling allowed the identification of node metastasis in 100% of the cases with a sensitivity of 100, specificity of 78 and a negative predictive value of 100 [15].

Conclusion

Cervical nodal involvement in the neck for the larynx and hypopharynx follows a predictable pattern. Cervical lymph node status is found to be the most important prognostic indicator. An elective lateral neck dissection (clearance of levels II–IV) is advisable in all advanced cases with laryngeal cartilage erosion, pyriform sinus lesions, supraglottic involvement and lesions with base of tongue involvement.