Influence of radiation dose to pharyngeal constrictor muscles on late dysphagia and quality of life in patients with locally advanced oropharyngeal carcinoma.

Abstract

Patients with oropharyngeal carcinoma (OPC) often have difficulty swallowing, which may affect quality of life (QoL). Radiation dose to constrictor muscles plays an important role. 54 patients with locally advanced OPC were evaluated after intensity-modulated radiotherapy. Data were collected at standardized intervals using the EORTC questionnaires QLQ-C30 and QLQ-HN35 within two years. The pharyngeal constrictors (superior, middle, and inferior) were each contoured as an organ at risk. Influence of dose to the constrictors (≥55Gy vs. <55Gy) on late dysphagia and QoL was analyzed using the t‑test. Late radiation-induced dysphagia depends significantly on the dose to the lower pharyngeal constrictor. At a dose of ≥55 Gy, 14 (64%) patients developed dysphagia grade ≤2 and 8 (36%) patients grade ≥3. At a dose of <55 Gy, the distribution at the end of radiotherapy (RT) was similar: 22 (69%) patients with dysphagia grade ≤2, 10 (31%) with grade ≥3. There was no dose-dependent difference in the severity of dysphagia in the acute phase (p = 0.989). There were differences 18 months after the end of RT: ≥55 Gy: 19 (86%) patients showed dysphagia grade ≤2; 3 (14%) grade ≥3. At <55 Gy, 31 (97%) patients developed grade ≤2, 1 (3%) grade ≥3 (18 months: p = 0.001; 24 months: p = 0.000). Late dysphagia is also dependent on the dose level of the middle constrictor muscle (6 months: p = 0.000; 12 months: p = 0.005, 18 months: p = 0.034). After 24 months, there was no significant difference (p = 0.374). Radiation dose to the upper constrictor muscle appears to be of little relevance. The middle and lower constrictor should be given special consideration to avoid late dysphagia. Long-term QoL is independent on radiation dose.