Clinical Outcome and Patterns of Recurrence of Head and Neck Squamous Cell Carcinoma with a Limited Field of Postoperative Radiotherapy

Background: Postoperative radiotherapy is the standard treatment for head and neck squamous cell carcinoma having high-risk features in surgical specimens. However, its severe toxicity can be a significant problem. This study was undertaken to evaluate the efficacy of our limited-field postoperative radiotherapy with the aim of reducing morbidity by minimizing the radiation field. Methods: Between 2000 and 2009, 154 patients with head and neck squamous cell carcinoma received limited-field postoperative radiotherapy. The reason for postoperative radiotherapy was close/positive margins in 33 patients and extracapsular extension in 91. The median radiation dose was 50 Gy (30–66.4). The radiation field covered the tumor bed without lymph node regions for close/positive margins and only involved sites of the neck region were irradiated for multiple nodes or extracapsular extension. Results: With a median follow-up of 43 months for surviving patients, the 3-year overall survival and progression-free survival rates were 53.7 and 42.1%, respectively. The 3-year rates of progression-free survival of the group having major risks (i.e. close/positive margins and/or extracapsular extension) and the group with other risks were 34.7 and 62.8%, respectively (P, 0.01). Thirty-one local recurrences (20%), of which 22 were located out-of-field, and 44 regional recurrences (29%), of which 16 were located out-of-field, developed. Late toxicity of grade 3 or greater developed in only six patients (3.8%). Conclusions: Although the toxicities associated with limited-field postoperative radiotherapy could be kept to lower levels, the locoregional control rate did not seem to be sufficient. We should arrange the radiation field depending on risk factors.