The impact of temporary iodine-125 interstitial implant boost in the primary management of squamous cell carcinoma of the oropharynx.

Abstract

To define the impact of interstitial boost of the oropharynx on local control and complications using iodine-125 (I-125) brachytherapy. Between October 1986 and September 1991, 19 patients with cancer of the oropharynx received treatment at William Beaumont Hospital. Primary tumors consisted of 13 base of tongue, 4 tonsillar, and 2 pharyngeal wall lesions. All patients received 45-66 Gy (median, 54 Gy) external beam irradiation to the primary and regional nodes, followed by an interstitial implant of 22-32 Gy (median, 25 Gy) with I-125. Median follow-up was 58 months (range, 12-89 months). Three patients failed within the tumor bed, for a 5-year actuarial rate of local control of 83% (T1/T2, 82%; T3/T4, 86%). Two of the three local failures were salvaged surgically, for an overall 5-year actuarial local control rate of 94%. The 5-year actuarial overall survival rate was 64%. Complications included one case of soft tissue ulceration and two cases of osteoradionecrosis, all managed conservatively. Patients with cancer of the oropharynx judged to be candidates for boosts with interstitial implants can be effectively treated with I-125. Local control was excellent, and complications were minimal.