Dysphagia disorders in patients with cancer of the oropharynx are significantly affected by the radiation therapy dose to the superior and middle constrictor muscle: a dose-effect relationship.
OBJECTIVE
To assess the relationship between the radiation therapy (RT) dose received by the muscular components of the swallowing (sw) apparatus and - dysphagia related - quality of life (QoL) in oropharyngeal cancer.


METHODS
Between 2000 and 2005, 81 patients with SCC of the oropharynx were treated by 3DCRT or IMRT, with or without concomitant chemotherapy (CHT); 43 out of these 81 patients were boosted by brachytherapy (BT). Charts of 81 patients were reviewed with regard to late dysphagia complaints; 23% experienced severe dysphagia. Seventeen patients expired. Fifty-six out of 64 (88%) responded to quality of life (QoL) questionnaires; that is, the Performance Status Scales of List, EORTC H&N35, and the M.D. Anderson Dysphagia Inventory. The superior (scm), middle (mcm), and inferior constrictor muscle (icm), the cricopharyngeus muscle and the inlet of the esophagus, are considered of paramount importance for swallowing. The mean dose was calculated in the muscular structures. Univariate analysis and multivariate analysis were performed using the proportional odds model.


RESULTS
Mean follow-up was 18 months (range 2-34) for IMRT, and 46 months for 3DCRT (range 2-72). At 3-years, a LRC of 84%, DFS of 78% and OS of 77% were observed. A significant correlation was observed between the mean dose in the scm and mcm, and severe dysphagia complaints (univariate analysis). A steep dose-effect relationship, with an increase of the probability of dysphagia of 19% with every additional 10 Gy, was established. In the multivariate analysis, BT (dose) was the only significant factor.


CONCLUSIONS
A dose-effect relationship between dose and swallowing complaints was observed. One way to improve the QoL is to constrain the dose to be received by the swallowing muscles.
Levendag
Peter C
PC
Department of Radiation Oncology, Erasmus Medical Center - Daniel den Hoed, Rotterdam, The Netherlands. p.levendag@erasmusmc.nl
Teguh
David N
DN
Voet
Peter
P
van der Est
Henri
H
Noever
Inge
I
de Kruijf
Wilhelmus J M
WJ
Kolkman-Deurloo
Inger-Karine
IK
Prevost
Jean-Briac
JB
Poll
Johan
J
Schmitz
Paul I M
PI
Heijmen
Ben J
BJ
D000328:Adult; D000368:Aged; D001918:Brachytherapy / Q000009:adverse effects*; D002294:Carcinoma, Squamous Cell / Q000523:psychology / Q000532:radiotherapy*; D003680:Deglutition Disorders / Q000209:etiology*; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009959:Oropharyngeal Neoplasms / Q000523:psychology / Q000532:radiotherapy*; D010609:Pharyngeal Muscles / Q000528:radiation effects*; D011788:Quality of Life; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal / Q000009:adverse effects*; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects*