Cancer of retromolar trigone: Long-term radiation therapy outcome

Background. Cancer of the retromolar trigone is an uncommon head and neck c ancer. in this retrospective study, we identified the prognostic factors an d evaluated the therapeutic outcomes of patients treated with preoperative radiation therapy (RT), postoperative RT, and RT alone. Methods. Between 1971 and 1994, 65 patients with histologically proven epid ermoid carcinoma of the retromolar trigone were treated at the Mallinckrodt Institute of Radiology; 10 patients received preoperative RT (30-55.2 Gy), 39 received postoperative RT (46-66.6 Gy), and 15 were treated with RT alo ne (63-74 Gy), Surgery included 44 composite resections and 7 wide excision s. The minimum follow-up was 5 years. Results. The 5-year disease-free survival rates were 90% with preoperative RT, 63% with postoperative RT, and 31% with RT alone. The 5-year disease-fr ee survival rates were 76% for patients with T1 disease, 50% for T2, 72% fo r T3, and 54% for T4. The 5-year disease-free survival rates were 69% for p atients with NO disease, 56% for N1, and 26% for N2. The locoregional recur rence rates were 10% (1 of 10) for preoperative RT, 23% (9 of 39) for posto perative RT, and 44% (7 of 16) for RT alone. On multivariate analysis, the significant factors for disease-free survival were treatment modality (p = .002) and N stage (p = .012); for locoregional control it was treatment mod ality (p = .046); and for distant metastasis it was N stage (p = .002). The Incidence of bone necrosis, soft tissue necrosis, and severe trismus was 1 2% with postoperative RT, 11% with RT alone, and none with preoperative RT. Conclusions, Combination surgery with postoperative or preoperative RT offe rs better locoregional control and disease-free survival than RT alone for epidermoid carcinoma of the retromolar trigone. Lymph node status significa ntly influences the disease-free survival and distant metastasis rates. (C) 2001 John Wiley & Sons, Inc.