Use of a conventional Low Neck Field (LNF) and intensity-modulated radiotherapy (IMRT): No clinical detriment of IMRT to an anterior LNF during the treatment of Head-and neck-cancer

Purpose: To determine differences in clinical outcomes using intensity-modulated radiotherapy (IMRT) or a standard low neck field (LNF) to treat low neck. Methods and Materials: This is a retrospective, single-institution study. Ninety-one patients with squamous cell carcinoma of the head and neck were treated with curative intent. According to physician preference, some patients were treated with LNF (Planning Target Volume 3) field using a single anterior photon field matched to the IMRT field. Field junctions were not feathered. The endpoints were time to failure and use of a percutaneous endoscopic gastrostomy (PEG) tube (as a surrogate of laryngeal edema causing aspiration), and analysis was done with χ ² and log-rank tests. Results: Median follow-up was 21 months (range, 2-89 months). Median age was 60 years. Thirty-seven patients (41%) were treated with LNF, 84% were Stage III or IV. A PEG tube was required in 30%, as opposed to 33% without the use of LNF. Node 2 or 3 neck disease was treated more commonly without LNF (38% vs. 24%, p = 0.009). Failures occurred in 12 patients (13%). Only 1 patient treated with LNF failed regionally, 4.5 cm above the match line. The 3-year disease-free survival rate was 87% and 79% with LNF and without LNF, respectively (p = 0.2), and the 3-year LR failure rate was 4% and 21%, respectively (p = 0.04). Conclusions: Using LNF to treat the low neck did not increase the risk of regional failure "in early T and early N diseases" or decrease PEG tube requirements.