Purpose: To evaluate irradiation alone for treatment of base-of-tongue cancer.
Patients and methods: Two hundred seventeen patients with squamous cell carcinoma of the base of tongue were treated with radiation alone and had follow-up for >/= 2 years.
Results: Local control rates at 5 years were as follows: T1, 96%; T2, 91%; T3, 81%; and T4, 38%. Multivariate analysis revealed that T stage (P =.0001) and overall treatment time (P =.0006) significantly influenced local control. The 5-year rates of local-regional control were as follows: I, 100%; II, 100%; III, 83%; IVA, 64%; and IVB, 65%. Multivariate analysis revealed that the following parameters significantly affect the probability of this end point: T stage (P =.0001), overall treatment time (P =.0001), overall stage (P =.0131), and addition of a neck dissection (P =.0021). The rates of absolute and cause-specific survival at 5 years were as follows: I, 50% and 100%; II, 81% and 100%; III, 65% and 76%; IVA, 42% and 56%; and IVB, 44% and 52%. Severe radiation complications developed in eight patients (4%).
Conclusion: The likelihood of cure after external-beam irradiation was related to stage, overall treatment time, and addition of a planned neck dissection. The local-regional control rates and survival rates after radiation therapy were comparable to those after surgery, and the morbidity associated with irradiation was less.