Retromolar trigone. A dreadful subsite of oral cancer

Abstract

Background: the retromolar trigone is an area of the oral mouth located behind the superior and inferior dental archs. Results of its treatment and overall survival has been sporadically published in retrospective series.
Objective: to discover factors which affect survival and free of disease interval in a series of patients under a preset protocol.
Methods: retrospective study, review of medical records and pathologic reports.
Results: The type of surgery in 90 patients included was: simple resection, 11; combined with marginal resection of mandible, 23; segmentary resection, 40 (7 of them reconstructed with fibula); and partial maxillectomy, 21. A supraomohyoid neck dissection was addedin 11/90 (12.2%) and a complete neck dissection of five levels, in 79/90 (97.8%). In 80.5% of the cases (83/103) received postoperative radiotherapy. In only 12.6% of the patients (13/103), preservation treatment with sequential chemo/radiotherapy was applied. Morbidity was 81.1 % and mortality 5.5%. Sixty four per cent of patients relapsed, with a 5 years average of 58.3%. In the multivariate analysis for recurrence, only margin resection was statistically significant. Five years overall survival was 46.7% and free of disease 39.1%. In multivariate analysis for survival, perineural invasion, margin resection and node metastases were statistically significant. 
Conclusions: The high number of patients not suitable por curative surgery usually affected by bone infiltration, perineural invasion or extension to the neck suggests that the retromolar trigone is a dreadful subsite for oral cancer.