Retromolar trigone squamous cell carcinoma: A population-based analysis of survival

To evaluate the difference in overall survival (OS) in patients with retromolar trigone squamous cell carcinoma (RMT SCC) treated with surgery alone versus surgery plus postoperative radiotherapy (PORT) versus surgery plus postoperative chemoradiotherapy (POCRT).

Retrospective cohort study of patients from 1,500 US facilities reporting to the National Cancer Database (NCDB) registry. Participants were adult patients treated with surgery as primary treatment modality for RMT SCC (n = 2,877). Exposures were primary definitive surgery versus surgery + PORT versus surgery + POCRT. Outcomes included OS after diagnosis and treatment of RMT SCC. A multivariate Cox proportional hazards model was constructed to compare survival between the three treatment modalities. Subgroup analysis was performed by T classification and overall staging.

There were 1,415 (50%) patients treated with surgery alone, 870 (30%) patients treated with surgery + PORT, and 572 (20%) treated with surgery + POCRT. Treatment with surgery + PORT was associated with improved OS compared to surgery alone (relative hazard: 1.25, 95% CI: 1.01, 1.54, p = 0.042). Patients treated with surgery + POCRT also had improved OS compared with surgery alone (relative hazard: 1.89, 95% CI 1.45, 2.43, p < 0.001). Patients with T3/4 tumors had improved OS when treated with surgery + PORT (relative hazard 1.39, 95% CI: 1.05, 1.84, p = 0.022) or surgery + POCRT (relative hazard 2.27, 95% CI: 1.66, 3.15, p < 0.001). Patients with T1 or T2 disease had no significant difference in survival in both the surgery + PORT (p = 0.331) and surgery + POCRT treatment groups (p = 0.134). Therefore, there was no difference in OS for patients with stage I or II disease treated with surgery + PORT (p = 0.451), nor with surgery + POCRT (p = 0.853).

Treatment with surgery + PORT +/- chemotherapy appears to be associated with significantly improved OS compared to surgery alone for advanced RMT SCCa.