Risk Factors Analysis of Pathologically Confirmed Cervical Lymph Nodes Metastasis in Oral Squamous Cell Carcinoma Patients with Clinically Negative Cervical Lymph Node: Results from a Cancer Center of Central China

Objective: To explore the risk factors of cervical lymph node metastasis in oral squamous cell carcinoma (OSCC) patients with clinical negative cervical lymph nodes(cN0) and provide a reference for clinical treatment. Methods: The clinical data of 161 OSCC patients with cN0 were retrospectively analyzed. All patients underwent extended primary resection combined with cervical lymph node dissection. The level and number of cervical lymph node metastasis were confirmed by postoperative pathology. The risk factors of cervical lymph node metastasis in patients were analyzed by univariate and multivariate Logistic regression analysis. Results: Thirty-one out of 161 cases (19%) were confirmed cervical lymph node metastasis. Among them, there were 28 cases of lymph node metastasis in one cervical level and 3 cases in two cervical levels. A total of 42 positive lymph nodes were detected in 34 cervical levels. The level number of positive areas in the IA, IB, IIA, IIB, III, IV and V levels was 2, 15, 12, 1, 4,0, and 0, respectively. The corresponding regional metastasis rates were 5.9%, 44.1%, 35.3%, 2.9%, 11.8%, 0% and 0%, respectively. The number of positive lymph node metastases in the corresponding levels were 2, 17, 17, 1, 5, 0, and 0 respectively. Univariate analysis showed that gender, age, lesion location, T stage, and perineural invasion/lymphvascular invasion (PNI/PVI) had no significant effect on cervical lymph node metastasis (P>0.05). The growth pattern, degree of differentiation, depth of invasion, neutrophil/lymphocyte ratio (NLR) and the short/long axis diameter ratio (S/L ratio) of lymph nodes were important factors influencing the cervical lymph node metastasis in cN0 OSCC patients (P<0.05). Multivariate Logistic regression analysis indicated that the growth pattern, degree of differentiation, depth of invasion, NLR, and the S/L ratio of lymph nodes were independent risk factors for cervical lymph node metastasis (P<0.05). Conclusion: The growth pattern, degree of differentiation, depth of invasion, neutrophil/lymphocyte ratio, and the short/long axis diameter ratio of lymph nodes were the independent risk factors for pathological cervical lymph node metastasis in oral squamous cell carcinoma patients with cN0. If patients with the above risk factors receive nonstandard radical neck dissection or no dissection, it may be necessary for them to receive the corresponding regional postoperative radiotherapy.