title: Neck spasm after chemoradiotherapy for head and neck cancer: natural history and dosimetric correlates.
abstract: BACKGROUND
  Little is known about the determinants of postradiation neck spasms in patients with head and neck cancer.
  
  
  METHODS
  Patients with head and neck cancer treated with radiation therapy (RT) from 2004 to 2010 who experienced neck spasms werereviewed. Radiation doses were generated for their sternocleidomastoid (SCM) muscles bilaterally. Unaffected SCMs were used as controls.
  
  
  RESULTS
  Thirty-four patients reported neck spasms. Thirty had received definitive chemoradiation, and 4 had RT alone. Seven also had an ipsilateral neck dissection. Median time to onset was 23 months (range, 6-67 months). There were significantly higher radiation doses to the affected SCMs with a median of the mean dose to the affected and unaffected SCM of 62.3 Gy (range, 29-71 Gy) and 53.7 Gy (range, 27-65 Gy), respectively (p < .0001). Other dosimetric variables were also statistically significant but were highly correlated with the mean SCM dose. Neck dissection did not affect our results.
  
  
  CONCLUSIONS
  Neck spasms after chemotherapy intensity-modulated radiation therapy (IMRT) shows a strong dose-response relationship.
authors.affiliation: Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan.
authors.forename: Klaudia U
authors.initials: KU
authors.lastname: Hunter
authors.forename: Francis
authors.initials: F
authors.lastname: Worden
authors.forename: Carol
authors.initials: C
authors.lastname: Bradford
authors.forename: Mark
authors.initials: M
authors.lastname: Prince
authors.forename: Scott
authors.initials: S
authors.lastname: McLean
authors.forename: Gregory
authors.initials: G
authors.lastname: Wolf
authors.forename: Douglas B
authors.initials: DB
authors.lastname: Chepeha
authors.forename: Avraham
authors.initials: A
authors.lastname: Eisbruch
mesh_terms: D000328:Adult; D000368:Aged; D059248:Chemoradiotherapy / Q000009:adverse effects*; D005260:Female; D005500:Follow-Up Studies; D006258:Head and Neck Neoplasms / Q000628:therapy; D006801:Humans; D008297:Male; D008875:Middle Aged; D037981:Neck Dissection / Q000379:methods; D009334:Neck Muscles / Q000528:radiation effects*; D011446:Prospective Studies; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D018714:Radiotherapy, Adjuvant / Q000009:adverse effects*; D012307:Risk Factors; D012720:Severity of Illness Index; D012907:Smoking / Q000009:adverse effects; D013035:Spasm / Q000175:diagnosis / Q000209:etiology*
keywords: complications; head and neck cancer; myoclonus; neck spasms; radiation