Patterns and risk factors of lymph node metastasis in locally advanced supraglottic squamous cell carcinoma

Abstract

Objective To investigate the pattern of lymph node metastasis (LNM) in patients with locally advanced (T3, T4) laryngeal squamous cell carcinoma (LALSC) and provide reference for the delineation of clinical target volume. Methods Clinical data of 272 patients with LALSC treated in our hospital from 2000 to 2017 were retrospectively analyzed. All patients underwent bilateral neck dissection (at least level Ⅱ-Ⅳ). The LNM ratio of each node level was calculated. The risk factors of LNM were identified by univariate and multivariate logistic regression analyses. Results LNM was found in 156 of 272 patients (57.1%). According to the location of primary lesions, all patients were divided into group A (n=72; unilateral without midline involvement), group B (n=86; unilateral with midline involvement) and group C (n=114; giant or central). In group A, the LNM ratio at ipsilateral level Ⅱ, Ⅲ and Ⅳ was 36.3%, 26.4% and 6.9%, whereas 13.9%, 8.3% and 1.4% at the contralateral level, respectively. In group B, the LNM ratio at ipsilateral level Ⅱ, Ⅲ and IV was 1.9%, 29.1% and 11.6%, whereas 18.6%, 14.0% and 1.2% at the contralateral level, respectively. In group C, the LNM ratio at the left neck level Ⅱ, Ⅲ and Ⅳ was 24.6%, 23.7% and 2.6%, whereas 21.9%, 26.3% and 6.1% at the right neck, respectively. Bilateral LNM ratio did not significantly differ between group A and group B/C (15.3%, 25.0%, P=0.093). Ipsilateral level Ⅲ metastasis (OR=2.929, 95%CI 1.041-8.245, P=0.042) and clinical N stage (OR=0.082, 95%CI 0.018-0.373, P=0.001) were associated with contralateral LNM. Ipsilateral level Ⅱ(P=0.043) or Ⅲ(P=0.009) metastasis were risk factors of the ipsilateral level Ⅳ metastasis. Conclusions Neck levels Ⅱ and Ⅲ are the high-risk LNM regions, whereaslevels Ⅳ and V are the low-risk areas. Ipsilateral level Ⅱ or Ⅲ metastases are the risk factors of ipsilateral level Ⅳ and contralateral cervical LNM. Contralateral neck LNM rarely occurs in cN0 stage patients. Key words: Locally advanced laryngeal cancer; Squamous cell carcinoma; Lymph node metastasis; Risk factor