Clinical outcome and patterns of recurrence of head and neck squamous cell carcinoma with a limited field of postoperative radiotherapy

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. 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. 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%). 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.