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

Background: To define the impact of interstitial boost of the oropharynx on local control and complications using iodine-125 (I-125) brachytherapy. Methods: 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. Results: 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. Conclusions: 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.