Primary oral squamous cell carcinoma: an analysis of 703 cases in southern Taiwan.

We retrospectively analyzed the records of 703 cases of oral squamous cell carcinoma (SCC) collected from 1 January 1985 to 31 December 1996 at a teaching hospital in southern Taiwan, to identify the characteristics of patients and factors associated with survival. There was an overwhelming male predominance (male:female = 15:1). The mean age of the patients was 52. The peak age of oral SCC patients declined from 50 to 59 years in the first six years (1985-1990) and 40-49 years in the last six years (1991-1996). The most common site of oral SCC was the buccal mucosa with 263 patients (37.4%). Most patients (346/703 patients; 49.2%) had stage III cancer. The most common site of occurrence of SCC was the buccal mucosa (263/703 patients; 37.4%), both overall and in patients who chewed betel quid alone or in combination with cigarette smoking and/or alcohol consumption; the tongue was the most common site among patients without any oral habits (18/48 patients; 37.5%). Furthermore, the age of occurrence was on average 6-12 years younger among patients who chewed betel quid than in those who did not. Of the 703 patients, 496 received treatment with surgery, chemotherapy, and/or radiation therapy. Of these, 209 (42.1%) died. The cancer stage significantly influenced mortality: the 5-year survival rate in patients treated from 1985 to 1991 was 72% in those with stage I, 38.9% in those with stage II, 26.7% in those with stage III, and 11.8% in those with stage IV cancer. Six variables were found to significantly affect survival: tumor size, lymph node involvement, surgery, betel quid chewing, staging, and histological differentiation (all p < 0.05, Kaplan-Meier analysis with log rank test). Of these, surgery and cancer stage independently affected survival in a proportional hazards model (both p < 0.0001). Therefore, the early surgical intervention, and the withdrawal from oral habits, especially betel quid chewing, will be advantageous to patients' survival.