Can IMRT or brachytherapy reduce dysphagia associated with chemoradiotherapy of head and neck cancer? The Michigan and Rotterdam experiences.
OBJECTIVE
Dysphagia is a major late complication of intensive chemoradiotherapy of head and neck cancer. The initial clinical results of intensity-modulated radiotherapy (IMRT), or brachytherapy, planned specifically to reduce dysphagia are presented.


METHODS
Previous research at Michigan University has suggested that the pharyngeal constrictors and glottic and supraglottic larynx are likely structures whose damage by chemo-RT causes dysphagia and aspiration. In a prospective Michigan trial, 36 patients with oropharyngeal (n = 31) or nasopharyngeal (n = 5) cancer underwent chemo-IMRT. IMRT cost functions included sparing noninvolved pharyngeal constrictors and the glottic and supraglottic larynx. After a review of published studies, the retropharyngeal nodes at risk were defined as the lateral, but not the medial, retropharyngeal nodes, which facilitated sparing of the swallowing structures. In Rotterdam, 77 patients with oropharyngeal cancer were treated with IMRT, three dimensional RT, or conventional RT; also one-half received brachytherapy. The dysphagia endpoints included videofluoroscopy and observer-assessed scores at Michigan and patient-reported quality-of-life instruments in both studies.


RESULTS
In both studies, the doses to the upper and middle constrictors correlated highly with the dysphagia endpoints. In addition, doses to the glottic and supraglottic larynx were significant in the Michigan series. In the Rotterdam series, brachytherapy (which reduced the doses to the swallowing structures) was the only significant factor on multivariate analysis.


CONCLUSIONS
The dose-response relationships for the swallowing structures found in these studies suggest that reducing their doses, using either IMRT aimed at their sparing, or brachytherapy, might achieve clinical gains in dysphagia.
Eisbruch
Avraham
A
Department of Radiation Oncology, University of Michigan, Ann Arbor, MI 48109-0010, USA. eisbruch@umich.edu
Levendag
Peter C
PC
Feng
Felix Y
FY
Teguh
David
D
Lyden
Teresa
T
Schmitz
Paul I M
PI
Haxer
Marc
M
Noever
Inge
I
Chepeha
Douglas B
DB
Heijmen
Ben J
BJ
D000704:Analysis of Variance; D001918:Brachytherapy; D003131:Combined Modality Therapy; D003680:Deglutition Disorders / Q000517:prevention & control*; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D008824:Michigan; D009303:Nasopharyngeal Neoplasms / Q000188:drug therapy* / Q000532:radiotherapy; D009426:Netherlands; D009959:Oropharyngeal Neoplasms / Q000188:drug therapy / Q000532:radiotherapy; D010609:Pharyngeal Muscles / Q000187:drug effects / Q000528:radiation effects; D011446:Prospective Studies; D050397:Radiotherapy, Intensity-Modulated