title: Malignant salivary gland tumours: can fast neutron therapy results point the way to carbon ion therapy?
abstract: OBJECTIVE
  To evaluate the outcome of malignant salivary gland tumours treated with neutron therapy to assess the potential for other high linear energy transfer (LET) beams.
  
  
  METHODS
  Neutrons at iThemba LABS are produced by the reaction of 66MeV protons on a beryllium target. A median dose 20.4Gy, in 12 fractions in 4weeks or 15 fractions in 5weeks, was given to 335 patients with 176 irresectable, 104 macroscopically residual and 55 unresected tumours.
  
  
  RESULTS
  Locoregional control was 60.6% at 5years and 39.1% at 10years and DSS was 66.8% and 53.7% at 5 and 10years respectively. In the univariate analysis T4, >4cm, high grade, squamous carcinoma, unresected and irresectable tumours, and positive nodes were significantly worse for LRC. In the multivariate analysis tumours >6cm, squamous carcinoma, irresectable tumours and nodes were significantly worse for LRC. Tumours >6cm, high grade, squamous carcinoma and nodes were significantly worse for DSS. Neither LRC nor DSS was influenced by age, sex, site, dose, fractionation or for initial or recurrent disease.
  
  
  CONCLUSIONS
  Neutron therapy appears to be the treatment of choice for macroscopically incompletely excised and irresectable salivary gland tumours with improved survival rates. Further improvement may be achieved with other high LET modalities with a superior dose profile, such as carbon ions.
authors.affiliation: Division of Radiation Oncology, University of Cape Town, South Africa. Electronic address: Clare.Stannard@uct.ac.za.
authors.forename: Clare
authors.initials: C
authors.lastname: Stannard
authors.forename: Frederik
authors.initials: F
authors.lastname: Vernimmen
authors.forename: Henri
authors.initials: H
authors.lastname: Carrara
authors.forename: Dan
authors.initials: D
authors.lastname: Jones
authors.forename: Shaheeda
authors.initials: S
authors.lastname: Fredericks
authors.forename: Jos
authors.initials: J
authors.lastname: Hille
authors.forename: Evan
authors.initials: E
authors.lastname: de Kock
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D005214:Fast Neutrons / Q000009:adverse effects / Q000627:therapeutic use; D005260:Female; D063193:Heavy Ion Radiotherapy / Q000009:adverse effects; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D012468:Salivary Gland Neoplasms / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*
keywords: Carbon ions; Head and neck cancer; High LET radiation therapy; Neutron therapy; Salivary gland tumours