Iodine-125 brachytherapy in the management of squamous cell carcinoma of the oral cavity and oropharynx.

PURPOSE: Brachytherapy is an acknowledged modality for treating head and neck cancers and has moved from low-dose-rate (LDR) to high-dose-rate remote afterloading to reduce staff exposure. Iodine-125 ((125)I) is a low-energy source and can be used for LDR brachytherapy with minimal staff exposure. The results of treating with this isotope at Groote Schuur Hospital, Cape Town, are reported here.

METHODS AND MATERIALS: (125)I brachytherapy was used to treat 114 tumors from 1994 to 2010. Brachytherapy alone was used for 72 tumors, 39 postsurgery and 33 de novo. A brachytherapy boost together with external beam radiotherapy was used for 42 tumors, eight postsurgery and 34 de novo. Tumors were in the tongue, floor of mouth, soft palate, and tonsil, and mainly T1 or T2 classification. Brachytherapy was administered via an applicator or in plastic tubes implanted into the soft tissues or through the submandibular region.

RESULTS

Local control rates of 80.7% at 5 years and 80% at 10 years were comparable to LDR, pulsed-dose-rate, and high-dose-rate results with iridium-192, likewise the 5- and 10-year disease-specific survival rate of 74.3%. Complications of soft tissue ulceration occurred in 21 patients (18.4%) and healed spontaneously in 20 patients. There was no mandibular necrosis.

CONCLUSIONS

(125)I can be used as the sole treatment or as a boost to external beam radiotherapy, with or without surgery for early mouth cancer. It combines the radiobiological advantages of LDR brachytherapy with minimum staff exposure. It is a flexible system. Local control is excellent with acceptable morbidity, and the treatment time is short.