Carcinoma of the tonsillar fossa: prognostic factors and long-term therapy outcome

To identify prognostic parameters and evaluate the therapeutic outcomes for patients with carcinoma of the tonsillar fossa treated with three treatment modalities.

The results of therapy are reported in 384 patients with histologically proven epidermoid carcinoma of the tonsillar fossa; 154 were treated with irradiation alone (55-70 Gy), 144 with preoperative radiation therapy (20-40 Gy), and 86 with postoperative irradiation (50-60 Gy). The operation in all but four patients in the last two groups consisted of an en bloc radical tonsillectomy with ipsilateral lymph node dissection.

Treatment modality and total irradiation doses had no impact on survival. Actuarial 10-year disease-free survival rates were 65% for patients with T1 tumors, 60% for T2, 60% for T3, and 30% for T4 disease. Patients with no cervical lymphadenopathy or with a small metastatic lymph node (N1) had better disease-free survival (60% and 70%, respectively) at 5 years than those with large or fixed lymph nodes (30%). Primary tumor recurrence (local, marginal) rates in the T1, T2, and T3 groups were 20-25% in patients treated with irradiation and surgery and 31% for those treated with irradiation alone (difference not statistically significant). In patients with T4 disease treated with surgery and postoperative irradiation, the local failure rate was 32% compared with 86% with low-dose preoperative irradiation and 47% with irradiation alone (p = 0.03). The overall recurrence rates in the neck were 10% for N0 patients, 25% for N1 and N2, and 35-40% for patients with N3 cervical lymph nodes, without significant differences among the various treatment groups. The incidence of contralateral neck recurrences was 8% with the various treatment modalities. On multivariate analysis the only significant factors for local tumor control and disease-free survival were T and N stage (p = 0.04-0.001). Fatal complications were noted in 7 of 144 (5%) patients treated with preoperative irradiation and surgery, 2 of 86 (2%) of those receiving postoperative irradiation, and 2 of 154 (1.3%) patients treated with radiation therapy alone. Other moderate or severe nonfatal sequelae were noted in 30% of the patients treated with preoperative irradiation and surgery, in 53% treated with postoperative irradiation, and in 19% receiving radiation therapy alone.

Primary tumor and neck node stage are the only significant prognostic factors influencing locoregional tumor control and disease-free survival. Treatment modality had no significant impact on outcome. Radiation therapy remains the treatment of choice for patients with stage T1-T2 carcinoma of the tonsillar fossa. In patients with T3-T4 tumors and good general condition, combination surgery and postoperative irradiation offers better tumor control than single-modality and preoperative irradiation procedures, but with greater morbidity.