Can the transoral approach secure a cancer-free deep margin in tonsil cancer?

To verify whether the submuscular plane of the constrictor muscle, which is the resection margin in a transoral approach, is sufficient for securing a cancer-free deep margin in tonsil cancer patients. Retrospective analysis of medical records and pathology specimens was done in sixty-two patients who were diagnosed with tonsil cancer and underwent surgery via a combined transoral-transcervical (transoral and transcervical lateral pharyngotomy) approach. The status of constrictor muscular invasion in tonsil cancer patients according to the TN stage and its predictors was investigated. Invasion or penetration of the constrictor muscle was found in three (27.3%), 30 (76.9%), and 12 (100%) stage T1, T2, and T3-4 patients, respectively. In the univariate analysis, invasion or penetration of the constrictor muscle was significantly correlated with gender (p = 0.004), stage >T2 (tumor ≥2 cm; p = 0.001), and N(+) (p = 0.004). The multivariate analysis showed that stage >T2 [tumor ≥2 cm; odds ratio (OR), 18.226; 95% confidence interval (CI), 2.976-111.608; p = 0.002] and N(+) (OR, 7.560; 95% CI, 1.478-38.671; p = 0.015) were significantly correlated with an increased risk of muscle invasion or penetration. The transoral approach is seems to be insufficient for securing a cancer-free deep margin in tonsil cancer beyond stage T2 or N1. The tumor beyond this stage should be treated more aggressively using multiple treatment modalities including radical surgery, chemotherapy, and radiotherapy.