Seven head and neck oncology cooperative groups in the Netherlands have reviewed the epidemiology, staging, treatment and survival of oropharyngeal carcinoma patients treated between 1986 and 1990. In all, 640 patients with squamous cell carcinoma (628, 98%) or undifferentiated carcinoma (12, 2%) referred for primary treatment were analyzed. The total group included 441 males (69%) and 199 females (31%), with a median age of 59 years (range, 30-92). Tumor distribution by subsite was the tonsillar region (372 patients, 58%), base of the tongue/vallecula (179, 28%), soft palate/uvula (62, 10%) and posterior oropharyngeal wall (27, 4%). Forty-four patients (7%) had stage I disease, 106 (17%) had stage II disease, 157 (24%) stage III, and 319 (50%) stage IV Staging was unknown in 14 patients (2%). Radiotherapy was given to the primary tumor in 408 patients (64%), surgery and radiotherapy to 147 (23%), surgery alone to 42 (7%), other treatments to 14 (2%) and no treatment to 29 patients (4%). The 5-year overall survival was 28% and the 5-year disease-specific survival was 41%. This latter survival was 35% in males and 51% in females (P = 0.003). Five-year survival by subsite was 54% in the soft palate/uvula, 42% in the tonsillar region, 33% in the base of the tongue and 32% in the posterior oropharyngeal wall (P = 0.003). When analyzing survival by stage, 5-year survival in patients with stage I disease was 68% and decreased significantly to 27% in stage IV disease (P < 0.001). Best survival occurred in patients treated with surgery alone (80%), was less in the group treated by surgery and radiotherapy (51 %), and decreased further in patients treated by radiotherapy alone (36%) (P < 0.0001). By multivariate analysis, stage, sex and midline localization were found to be si