Reirradiation With Simultaneously Integrated Boost (SIB) in Patients With Local Recurrence of Squamous Cell Carcinoma of the Head and Neck: Own Experience

Abstract

Locoregional recurrence is a major cause of death in patients with squamous cell carcinoma of the head and neck (HNSCC). At the moment, there are no clear recommendations and standards regarding the timing, total doses, and dose tolerance of normal tissues to re-exposure. Based on limited studies on the reirradiation with high total doses, we evaluated the tolerability of high-dose reirradiation with simultaneous integrated boost. Fourteen patients with histologically confirmed locoregional recurrence of HNSCC received reirradiation. Median time after primary radiation therapy course was 60 months. The treatment volumes and total doses were formed as follows: gross tumor volume (primary lesion and involved lymph nodes, delineated on computed tomography [CT], magnetic resonance imaging, and 18F-fluorodeoxyglucose positron emission tomography/CT) + clinical target volume (0.5-1.0 cm) + planning target volume (PTV; 0.3-0.5 cm) was treated to the total dose equivalent to 66 to 70 Gy of conventional fractionation, the upper neck (if indicated, levels I-III + PTV 0.5 cm) to 60 Gy, the lower neck (if indicated, levels IV-V + PTV 0.5 cm) – equivalent to 50 Gy. Single doses to these volumes were 2.14 to 2.21 Gy, 2.0 Gy, and 1.8 Gy, respectively. Radiation treatment was once a day, 5 days a week, 6 weeks long (30 fractions). A treatment planning system was used (intensity modulated radiation therapy [IMRT]), and patients were treated with 2 linear accelerator models. According to the literature, in a year after primary irradiation, almost complete recovery of normal tissue tolerances is observed. Tolerances of the eye, lens, optic nerves and chiasm, brain stem, spinal cord, parotid gland, intact mucosa of the mouth and pharynx were not exceeded. Patient positioning accuracy was controlled by kV-imaging daily and cone beam CT weekly. Three of 14 patients received the full course of radiation therapy without a break. Radiation toxicity manifested with grade 2 oral and pharyngeal mucositis and grade 2 radiation epidermitis. After 1 month, almost complete relief of radiation mucositis and dermatitis was observed. One patient took a break of 7 days after the 25th fraction due to the development of grade 3 mucositis and grade 3 dysphagia. Using the technique of SIB with IMRT during curative reirradiation of recurrent HNSCC is available with maintaining satisfactory tolerability.