[Intensity modulated radiotherapy for head and neck cancer, dose constraint for normal tissue: Cochlea vestibular apparatus and brainstem].
Modern techniques such as intensity modulated radiation therapy (IMRT) have been proven to significantly decrease the dose delivered to the cochleovestibular apparatus, limiting consecutive toxicity especially for sensorineural hearing loss. However, recent data still report a 42% rate of radio-induced hypoacusia underscoring the need to protect the cochleovestibular apparatus. Due to the small size of the cochlea, a precise dose-volume analysis could not be performed, and recommendations only refer to the mean dose. Confusing factors such as age, concomitant chemotherapy, primary site and tumor stage should be taken into account at the time of treatment planning. (Non-coplanar) VMAT and tomotherapy have been proven better at sparing the cochlea in comparison with 3D CRT. Brainstem radio-induced injuries were poorly studied because of their infrequency and the difficulty of distinguishing between necrosis and tumor progression in the case of a primary tumor located at the base of skull. The following toxicities have been described: brainstem focal radionecrosis, cognitive disorders without dementia, cranial nerve injuries and sensori motor disability. Maximal dose to the brainstem should be kept to < 54Gy for conventional fractionation. This dose could be exceeded (no more than 10mL should receive more than 59Gy), provided this hot spot is located in the peripheral area of the organ.
Département de radiothérapie, centre Léon-Bérard, 28, rue Laënnec, 69008 Lyon, France.
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Guimas
Département de radiothérapie, centre Antoine-Lacassagne, 33, avenue Valombrose, 06189 Nice, France.
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Thariat
Département de radiothérapie et de curiethérapie, institut universitaire du cancer de Toulouse-Oncopôle, 1, avenue Irène-Joliot-Curie, 31059 Toulouse, France.
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Graff-Cailleau
Département de radiothérapie, institut du cancer de Montpellier, 208, avenue des Apothicaire, 34298 Montpellier, France.
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Boisselier
Clinique Victor-Hugo, institut interrégional de cancérologie, centre Jean-Bernard, 9, rue Beauverger, 72000 Le Mans, France.
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Pointreau
Département de radiothérapie, centre Léon-Bérard, 28, rue Laënnec, 69008 Lyon, France.
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Pommier
Département de radiothérapie, centre Léon-Bérard, 28, rue Laënnec, 69008 Lyon, France.
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Montbarbon
Département de radiothérapie, centre Léon-Bérard, 28, rue Laënnec, 69008 Lyon, France.
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Laude
Département de radiothérapie, centre Léon-Bérard, 28, rue Laënnec, 69008 Lyon, France. Electronic address: severine.racadot@lyon.unicancer.fr.
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Racadot
D001933:Brain Stem / Q000528:radiation effects*; D003051:Cochlea / Q000528:radiation effects*; D003072:Cognition Disorders / Q000209:etiology / Q000517:prevention & control; D020209:Cranial Nerve Injuries / Q000209:etiology / Q000517:prevention & control; D004307:Dose-Response Relationship, Radiation; D006258:Head and Neck Neoplasms / Q000532:radiotherapy*; D006319:Hearing Loss, Sensorineural / Q000209:etiology / Q000517:prevention & control; D006801:Humans; D000068079:Motor Disorders / Q000209:etiology / Q000517:prevention & control; D009336:Necrosis / Q000209:etiology / Q000517:prevention & control; D058958:Organs at Risk; D011879:Radiotherapy Dosage; D050397:Radiotherapy, Intensity-Modulated
Appareil cochléovestibulaire; Brainstem; Cochlea vestibular apparatus; Head and neck cancer; IMRT; Inner ear; RCMI; Tronc cérébral; Tumeurs des VADS