Objective: To determine which clinical and pathologic features are associated with regional metastases in patients with lower gingival squamous cell carcinoma.
Patients and methods: The medical charts of 155 previously untreated patients seen between 1970 and 1990 were retrospectively analyzed. All patients underwent surgical resection of the primary tumor. In addition, 66 patients underwent elective neck dissection, while a therapeutic neck dissection was performed in 28. Sixty-one patients who had clinically N0 neck disease did not undergo treatment of the cervical lymphatics.
Results: T stage (P = .01), radiologic (P = .03) or histologic (P = .01) evidence of mandibular invasion, and decreased tumor differentiation (P = .004) significantly correlated with the presence or evolution of regional metastases. In addition, tumors involving the symphyseal region were associated with an increased incidence of nodal metastases, although the relationship did not achieve statistical significance (P = .08). Occult regional disease was found in 18% of patients who underwent elective neck dissection, and the presence of metastases was pathologically confirmed in 68% who underwent a therapeutic dissection. Six patients with clinically N0 neck disease did not undergo elective dissection and later developed regional metastases. In all patients, survival was adversely impacted by the presence or later development of regional metastases (P < .001). Two- and 5-year survival rates for patients with no cervical metastases were 0.91 and 0.85, respectively, while for those with cervical metastases, the survival at 2 and 5 years declined to 0.72 and 0.59. More importantly, the 2- and 5-year survivals of patients with clinically N0 necks who were found to have lymph node metastases histologically after neck dissection were 1.00 and 0.78. This contrasts with the 0.50 survival rate at 2 and 5 years for those who did not undergo elective dissection and later developed cervical metastases (P = .36).
Conclusions: Patients with adverse clinical and pathologic features, even in the absence of demonstrable neck disease, are at risk for harboring regional metastases. Elective treatment of the cervical lymphatics should be considered for patients with primary tumors that overlie the mandibular symphysis, moderately or poorly differentiated tumors, or radiographic or histologic evidence of mandibular invasion.