Objective
To determine whether invasion of the pharyngeal constrictor muscle in early squamous cell carcinoma of the tonsil is correlated with lymph node metastasis.
Design
Retrospective analysis of medical records and pathology specimens.
Setting
Tertiary care referral center.
Patients
Forty-eight patients who were diagnosed as having T2 squamous cell carcinoma of the tonsil and who underwent surgery. They were divided into 2 groups: an invasive group with invasion of the pharyngeal constrictor muscle and a noninvasive group without invasion of the pharyngeal constrictor muscle.
Main Outcome Measures
Comparison of regional metastasis, 5-year locoregional recurrence, and 5-year disease-specific survival between the 2 groups.
Results
Invasion of the pharyngeal constrictor muscle was found in 36 patients (75%) with T2 squamous cell carcinoma of the tonsil. The rate of lymph node metastasis, the mean (SD) number of positive nodes, and the mean (SD) lymph node density were 81%, 5.47 (9.27), and 0.15 (0.22) in the invasive group, respectively, and 50%, 1.33 (1.72), and 0.04 (0.04) in the noninvasive group, respectively (P = .04, P = .02, and P = .01, respectively). Five-year locoregional recurrence was significantly correlated with invasion of the pharyngeal constrictor muscle (P = .05) and with multiple lymph node metastasis (≥5 nodes) (P = .04) in the univariate analyses. No factor was correlated with 5-year locoregional recurrence in the multivariate analysis. Five-year disease-specific survival was significantly correlated with multiple lymph node metastasis (≥5 nodes) in the univariate analyses (P = .009). Five-year disease-specific survival was not significantly correlated with any clinicopathological factor in the multivariate analysis.
Conclusion
Higher risk for multiple lymph node metastasis and 5-year locoregional recurrence seems to be predicted in patients with extratonsillar invasion of the pharyngeal constrictor muscle, even in early squamous cell carcinoma of the tonsil.