A Pilot Study Using Intraoperative Placement of Cesium-131 Permanent Interstitial Brachytherapy in Resectable High Risk Recurrent Head and Neck Cancer

Abstract

To determine the feasibility and safety of Cesium-131 implant in the management of recurrent head and neck cancer (HNC). This is a prospective trial approved by institutional IRB. Eligibility includes patients with resectable, recurrent failures who had a prior history of radiation to the head and neck deemed high risk for a second failure by our multidisciplinary tumor board. The strength and numbers of the Cesium 131 seeds were estimated based on a preoperative treatment plan with diagnostic CT images. Immediately after tumor extirpation, the seeds were implanted in the surgical bed based on the preoperative treatment plan with intraoperative adjustment. The surgical bed and the seeds were covered with a regional flap or microvascular free flap. A CT of neck was obtained on postoperative day 1 to confirm the dose distribution of the implant. The patient followed up at 1 month and 3 months after surgery, then every 3 months in the first two years. PET/CT scans or CT neck and chest with contrast was obtained at 3 months and one year after surgery. From November 2016 to September 2018, 15 patients were recruited, and 12 patients received protocol treatment. Of the three patients who did not receive protocol treatment, one had disease progression before surgery and went hospice, and two were determined to be low risk intraoperatively. Ninety-two percent (n=11) of the patients were male with a median age of 74.5 years old (range: 52-86). Primary sites included 5 oropharynx, 3 larynx, 3 skin, and 1 oral cavity. Recurrent sites included 10 neck alone, 1 neck and larynx, and 1 neck/peristomal. The interval between recurrence and previous radiation ranged from 3.7 – 103.8 months. Cesium implant dose ranged from 60 to 70 Gy. After surgery, patients remained in the hospital 3 to 9 days (median 6 days). There were no significant toxicities, and only one patient developed superficial wound breakdown requiring local wound care. The median follow-up was 10.1 months (range: 2.6 to 23.9) after implant. At last follow up, 5 patients had recurrence: 1 local, 2 distant, and 2 with both local and distant recurrences. Of the 3 local recurrences, only 1 had in-field failure. One patient failed in the contralateral neck and one in ipsilateral neck distant from the implant. Three patients had died, 2 with recurrences and 1 died of other cause with no recurrence. Intraoperative Cesium 131 implantation after surgical resection in recurrent HNC is feasible and safe. There were no unexpected severe toxicities. Most failures were out-of-field and distant failures. Future clinical trial with combination of cesium 131 implant and immunotherapy is under development.