Squamous cell carcinoma of cervical lymph nodes from an unknown primary site: The impact of neck dissection.

OBJECTIVE: To investigate the treatment strategies of squamous cell carcinoma of cervical lymph nodes from an unknown primary site (SCCUP) and the value of neck dissection (ND).

MATERIALS AND METHODS: The study included 133 patients referred to the Zhejiang Cancer Hospital from 2001 to 2012, with 109 males and 24 females. Distribution of patients by N status was as follows: N1 - 14 cases; N2a - 21 cases; N2b - 78 cases; N2c - 7 cases; and N3 - 13 cases. 104 patients underwent surgeries of ND while 29 patients underwent nonsurgical treatment. Among 104 patients, 24 underwent classic radical ND, 16 modified ND, 53 selective ND, and 11 extended ND. The selection of surgical strategy was determined by the extent and location of disease. According to the range of ND, 50 patients underwent ND for Levels I-V, 46 for Levels II-V, 4 for Levels I-III, 3 for Levels II-VI, and 1 for Levels I-VI. The data were analyzed with SPSS version 16.0. The differences between groups were calculated by χ2 tests. The actual overall survival (OS) rates were calculated by the Kaplan-Meier method. Different factors affecting the OS were determined by the log-rank test on univariate analysis. Cox regression was used to evaluate the multivariate analysis.

RESULTS: The 5-year OS rate of the whole cohort was 67.1%; and the median survival time was 70.0 months. The 5-year OS of ND group and of the non-ND group were 71.3% and 53.2%, respectively (P = 0.061). Cox analysis indicated that N stage (P = 0.000), bilateral neck metastasis (P = 0.001), extracapsular spread (ES) (P = 0.016), and ND (P = 0.028) were independent prognostic factors for the OS of SCCUP. 25 patients (18.8%) had neck recurrence or residue. The locoregional failure rate of ND group and of the non-ND group were 13.5% and 37.9%, respectively (P = 0.003). Logistic regression analysis indicated that higher N stage was the main risk factor for locoregional failure (P = 0.015).

CONCLUSION: N stage, bilateral neck metastasis, ES, and ND were the main factors for the survival rate of SCCUP. N3 stage was the independent risk factor for locoregional failure. ND could significantly increase the locoregional control and may benefit the survival rate.