Intraoperative Radiation Therapy in Head and Neck Cancers

Abstract

Abstract: Management of recurrent/persistent Head and Neck Cancers is a major challenge for the radiation oncologist. Current rate of loco-regional recurrence for head and neck cancers is 40-50%. The primary salvage modality for resectable cases is surgery often followed by adjuvant chemo-radiotherapy. Traditional postoperative radiation therapy is 50-60 Gy delivered 5-6 week after surgery. There are numerous pitfalls of this practice: uncertainty of clinical target volume, tumor cell proliferation during waiting period, and inconvenience of six weeks travel to the department of radiation therapy, to name a few. Intraoperative radiation therapy (IORT) has been shown to be a great help in addressing some of these concerns. Greater accuracy of target volume at the time of surgery, avoidance of cell proliferation during the waiting period, and elimination or reduction in visits to the department of radiation oncology are some of its advantages. Modern IORT is based on the availability of mobile linear accelerators capable of delivering high dose of radiation in one fraction to a defined volume at the time of surgery. Most of the literature is on the use of remote after-loading catheters and/or electron beams. Hereby we report the first experience of using INTRABEAM IORT (Zeiss Corporation, Mannheim, Germany) in treating recurrent head and neck cancers. The system is based on delivering a high dose of low-energy (50 keV) X-rays in one fraction at the time of surgery. To our knowledge this is the first report of using this system in recurrent head and neck cancer setting. From March 2014 to 2016 we have treated 22 patients with recurrent or advanced head and neck cancers with IntraBeam device. Of these seven patients had primary parotid tumors and the rest were either recurrent at the parotid site or in the neck. IORT dose, prescribed to 5 mm depth, was either 5Gy boost or 12-14 Gy definitive dose. We have used FLAT applicators in size ranging from 4 - 6 cm in diameter. 10 of 22 patients also had 40-50 Gy external beam radiation therapy, based on permanent pathological findings. With a median follow up of 16 months (range: 3-33 months) IORT in-field local control was achieved in 19 of 22 patients with two additional patient follow up while tumor was under control. Complications included wound healing(1 patient), fat necrosis(1 patient), and two patients with radiation induced neuropathies. Our preliminary data suggest that a high dose of IORT with low energy (50 keV) X-rays is a safe and effective alternative to conventional treatment modalities. Detailed data will be presented. To our knowledge this is the first reported use of INTRABEAM IORT in recurrent head and neck cancer patients.