Clinical outcome and toxicity after simultaneous integrated boost IMRT in head and neck squamous cell cancer patients

A simultaneous integrated boost (SIB) intensity modulated radiotherapy (IMRT) in patients with head and neck squamous cell carcinoma (HNSCC) allows to irradiate different target volumes to different dose levels within a single treatment session without increasing the toxicity.

To analyze the outcome and toxicity of patients treated by definitive or postoperative SIB IMRT for HNSCC.

106 patients with HNSCC of the oral cavity (OC), oropharynx (OP), larynx (L) and hypopharynx (HP), consecutively treated at our cancer center between 3/2012 and 3/2014 were retrospectively analyzed. The prescribed SIB IMRT doses were in the postoperative setting (group A) 60-66 Gy and 53 Gy in 30-33 fractions for PTV high risk and PTV elective, respectively; and 70 Gy and 56 Gy in 35 fractions for PTV high risk and PTV elective, respectively when given as primary treatment (group B). Toxicity was consistently graded according to RTOG/EORTC scale.

Median follow-up duration was 31 months. Thirty (28%) patients were postoperatively irradiated (group A) and 76 (72%) patients received definitive IMRT (group B). At 3 years, loco-regional control, distant control and overall survival were 78%, 78%, 57% and 64%, 76%, 52% in the postoperative (group A) and the definitive SIB IMRT group (group B), respectively. The observed acute grade 3 toxicities were dysphagia (44%), oral and/or oropharyngeal mucositis (40%) and dermatitis (21%). Late toxicity was predominantly clinically significant xerostomia (42%), dysgeusia (23%) and dysphagia (8%).

SIB IMRT is feasible, safe and effective in the treatment of HNSCC patients.