1008: Dysphagia Related Quality of Life of Patients With Cancer in the Oropharynx Is Significantly Affected by the Radiation Therapy Dose Received by the Superior- and Middle Constrictor Muscle: A Dose-Effect Relationship

Abstract

To assess the correlation between dose received in the swallowing (sw) apparatus and decrement in the quality of life (QOL) of patients with oropharyngeal cancer. Between 2000-2005, 77 patients with scc of the tonsillar fossa and/or soft palate and the base of tongue, were analyzed for dysphagia after having been treated by intensity modulated- (n=37), 3D conformal- (n=22) or CT-based parallel-opposed (n=18) radiotherapy (RT) techniques. In 52% brachytherapy (BT) was used, in 47% radiation was combined with concomitant chemotherapy (cCHT). Five structures, being the superior-, middle-, and inferior constrictor muscles (scm, mcm, and icm, respectively), the cricopharyngeus muscle and the muscular inlet of the esophagus, are of paramount importance for swallowing. The treatment plans of all patients were retrieved; in every axial CT slice the 5 muscular structures were delineated and mean dose calculated (DVHs). Three validated Quality of Life (QOL) questionnaires were used: the Performance Status Scale of List, scoring for “eating in public” and “normalcy of diet”, the EORTC H&N 35 items swallowing liquids, pureed food, solid food and aspiration while eating, and the M.D. Anderson Dysphagia Inventory, 20 item - dysphagia specific - QOL questionnaire for Head and Neck cancer (MDADI). Universityariate analysis is performed, correlating the mean dose in the 5 sw muscles with the outcome of the questionnaires, using the proportional odds model. In a multivariate analysis the effects of the parameters age, sex, site, T-stage, N-stage, dose, technique, surgery, chemotherapy and brachytherapy were studied. Out of the 77 patients, 60 were re-examined in 2005 and found to be NED; 5 had previously expired (local failure) and 12 died because of intercurrent disease. Mean FU was 41 mo. (4-72). At 5-yrs the local relapse free survival was 92%, overall survival 65 %. In contrast to parameters ‘treatment techniques’ and ‘CHT’, in each QOL instrument, BT seems to project a favorable outcome (p=0.01). In the univariate analysis a significant correlation was observed between dose in the scm & mcm and the outcome of H&N 35 and MDADI. In a multivariate analysis, BT was the only significant factor (p=0.01). From figure 1, one can appreciate the steep relationship between dose in the scm & mcm and probability of sw complaints. The multivariate analysis shows a significant effect of BT, which suggests less sw complaints with lower doses. Therefore, improving QOL needs further optimization of the dose in the scm & mcm in particular.