Prognostic factors in intraoral squamous cell carcinoma: the influence of histologic grade

Abstract

Purpose: The purpose of this retrospective study was to review the outcome of patients with oral cavity squamous cell carcinoma treated at a single institution by primary surgical resection with or without adjuvant radiotherapy or chemoradiotherapy and to identify factors affecting survival and locoregional control.

Patients and methods: The records of 233 patients with oral cavity squamous cell carcinoma treated at a single institution from 1993 to 2003 were identified from the Legacy Emanuel Hospital and Health Center's cancer registry (Portland, OR). All patients undergoing surgical resection as a primary treatment modality were included in the study. Patients with nonresectable disease, distant metastasis, and those with inadequate follow-up data were excluded from the study. Patients with positive surgical margins, high-grade histology, aggressive biologic behavior, or advanced staged disease underwent adjuvant radiotherapy or chemoradiotherapy. The data collected included age, gender, race, tumor site, margin status, grade, TNM stage, cancer therapies, and cancer status. Data were statistically analyzed in an attempt to identify predictors of locoregional control and disease-free survival. Descriptive statistics were calculated for each variable and survival was calculated using the Kaplan-Meier method. Prognostic factors were analyzed using the Cox proportional hazard model.

Results: Two hundred fifteen patients consisting of 119 men (55%) and 123 females (52%), with an average age at diagnosis of 66 years (SD +/- 14), met the criteria for inclusion in the study. Average tumor size was 23.5 mm (SD +/- 14.1). Overall 5-year survival was 56% and disease-free survival at 5 years was 58%. Stage and grade were identified as having a statistically significant effect on survival (P = .014; likelihood ratio chi-square = 10.7, 3 degrees of freedom; and P = .026; likelihood ratio chi-square = 5, 1 degree of freedom, respectively). Neither age, gender, race, tumor site, nor positive margins showed a statistically significant effect on survival (P > .05).

Conclusion: This study highlights the importance of grade and stage as independent factors in predicting survival in patients with oral squamous cell carcinoma.