Marginal misses after postoperative intensity-modulated radiotherapy for head and neck cancer.

Purpose: To describe the spatial distribution of local-regional recurrence (LRR) among patients treated postoperatively with intensity-modulated radiotherapy (IMRT) for head and neck cancer.

Methods And Materials: The medical records of 90 consecutive patients treated by gross total resection and postoperative IMRT for squamous cell carcinoma of the head and neck from January 2003 to July 2009 were reviewed. Sites of disease were the oral cavity (43 patients), oropharynx (20 patients), larynx (15 patients), and hypopharynx (12 patients). Fifty patients (56%) received concurrent chemotherapy.

Results: Seventeen of 90 patients treated with postoperative IMRT experienced LRR, yielding a 2-year estimate of local regional control of 80%. Among the LRR patients, 11 patients were classified as in-field recurrences, occurring within the physician-designated clinical target volume, and 6 patients were categorized as marginal recurrences. There were no out-of-field geographical misses. Sites of marginal LRRs included the contralateral neck adjacent to the spared parotid gland (3 patients), the dermal/subcutaneous surface (2 patients), and the retropharyngeal/retrostyloid lymph node region (1 patient).

Conclusions: Although the incidence of geographical misses was relatively low, the possibility of this phenomenon should be considered in the design of target volumes among patients treated by postoperative IMRT for head and neck cancer.