title: Radiation-induced lower cranial nerve palsy in patients with head and neck carcinoma.
abstract: Radiation-induced cranial nerve palsy (RICNP) is a severe long-term complication in patients with head and neck cancer following high-dose radiation therapy (RT). We present the case report of a patient with bilateral RICNP of the hypoglossal and vagus cranial nerves (XII/X) following postoperative RT in the era prior to the introduction of intensity-modulated RT (IMRT), and an analysis of our IMRT patient cohort at risk including the case of a XII RICNP. A total of 201 patients whose glosso-pharyngeal (IX), X and XII cranial nerves had been exposed to >65 Gy definitive IMRT in our institution between January, 2002 and December, 2012 with or without systemic therapy, were retrospectively identified. A total of 151 patients out of 201 fulfilling the following criteria were included in the analysis: Locoregionally controlled disease, with a follow-up (FU) of >24 months and >65 Gy exposure of the nerves of interest. So far, one of the assessed 151 IMRT patients at risk exhibited symptoms of RICNP after 6 years. The mean/median FU of the entire cohort was 71/68 months (range, 27-145). The results were compared with literature reports. In conclusion, RICNP appears to be a rare complication. However, a longer FU and a larger sample size are required to draw reliable conclusions on the incidence of RICNP in the era of IMRT.
authors.affiliation: Department of Radiation Oncology, University Hospital of Zurich, 8091 Zurich, Switzerland ; Department of Radiation Oncology, University of Lübeck, 23562 Lübeck, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Janssen
authors.affiliation: Department of Radiation Oncology, University Hospital of Zurich, 8091 Zurich, Switzerland.
authors.forename: Christoph
authors.initials: C
authors.lastname: Glanzmann
authors.affiliation: Department of Radiation Oncology, University Hospital of Zurich, 8091 Zurich, Switzerland.
authors.forename: Bita
authors.initials: B
authors.lastname: Yousefi
authors.affiliation: Department of Radiation Oncology, University Hospital of Zurich, 8091 Zurich, Switzerland.
authors.forename: Karl
authors.initials: K
authors.lastname: Loewenich
authors.affiliation: Department of Otorhinolaryngology, Head and Neck Surgery, University Hospital of Zurich, 8091 Zurich, Switzerland.
authors.forename: Gerhard
authors.initials: G
authors.lastname: Huber
authors.affiliation: Department of Otorhinolaryngology, Bethanien Hospital, 8044 Zurich, Switzerland.
authors.forename: Stephan
authors.initials: S
authors.lastname: Schmid
authors.affiliation: Department of Radiation Oncology, University Hospital of Zurich, 8091 Zurich, Switzerland.
authors.forename: Gabriela
authors.initials: G
authors.lastname: Studer
keywords: intensity-modulated radiation therapy; lower cranial nerves; radiation tolerance; radiation-induced cranial nerve palsy