title: Number needed to treat analysis for planned neck dissection after chemoradiotherapy for advanced neck disease.
abstract: OBJECTIVE
  to analyze how many planned neck dissections (PNDs) must be performed to prevent one fatal neck recurrence after chemoradiotherapy for head and neck cancer with regional metastasis.
  
  
  METHODS
  a systematic literature review of studies using chemoradiotherapy as primary treatment for head and neck cancer was performed. Data were extracted where possible to determine estimates for the following variables: (1) percentage of N2-3 necks still harbouring cancer after chemoradiotherapy as proven by pathology from neck dissection (C); (2) percentage of regional recurrence after PND (P); (3) percentage of regional recurrence after salvage neck dissection for patients without initial PND in whom neck disease recurred after chemoradiotherapy (S); and (4) mortality rate of PND (M). The number needed to treat was calculated using the following equation: NNT = 1/[C*(S+M) - (P+M)].
  
  
  RESULTS
  the number needed to treat is 7.5.
  
  
  CONCLUSIONS
  to prevent one fatal neck recurrence after chemoradiotherapy for head and neck cancer with N2-3 disease, one would need to perform 7.5 PNDs. The results of this study will aid surgeons and patients in making more informed decisions regarding neck dissections.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, The Ottawa Hospital, ON. hedyeh2@yahoo.com
authors.forename: Hedyeh
authors.initials: H
authors.lastname: Javidnia
authors.forename: Martin J
authors.initials: MJ
authors.lastname: Corsten
mesh_terms: D003131:Combined Modality Therapy; D006258:Head and Neck Neoplasms / Q000473:pathology / Q000628:therapy*; D006801:Humans; D008207:Lymphatic Metastasis; D009333:Neck / Q000473:pathology; D037981:Neck Dissection; D009364:Neoplasm Recurrence, Local / Q000473:pathology / Q000517:prevention & control*