title: PET/CT-based metabolic tumour volume for response prediction of neoadjuvant chemoradiotherapy in oesophageal carcinoma.
abstract: OBJECTIVE
  Neoadjuvant chemoradiotherapy is increasingly used in oesophageal cancer patients. In general, small tumours are associated with a survival benefit compared to large tumours. Little is known, however, about the relationship between initial tumour volume and response to chemoradiotherapy. Therefore, the aim of this study was to determine whether the pretherapy metabolic tumour volume (MTV) on diagnostic PET/CT in oesophageal cancer patients is correlated with response to chemoradiotherapy in the resection specimen.
  
  
  METHODS
  A consecutive series of patients underwent diagnostic PET/CT scanning prior to chemoradiotherapy and oesophagectomy. MTVs were determined on PET/CT and an automated tumour contour was generated using specified standard uptake value thresholds. Response to chemoradiotherapy was determined in the resection specimen according to the scoring system developed by Mandard et al. Patients were divided into different groups according to response to chemoradiotherapy.
  
  
  RESULTS
  Between January 2008 and May 2011 a total of 115 patients underwent an oesophagectomy. The MTV determined on diagnostic PET/CT scans was available in 79 patients. Of these 79 patients, 30 (38 %) showed no residual tumour cells at the location of the primary tumour. Three of these patients presented with residual tumour cells in the lymph nodes; 27 patients (34 %) had a complete pathological response. There was a trend towards a better response in patients with a smaller MTV (p = 0.084).
  
  
  CONCLUSIONS
  This study demonstrated a trend towards a correlation between response to chemoradiotherapy in oesophageal cancer patients and smaller MTVs as determined on diagnostic PET/CT prior to neoadjuvant chemoradiotherapy. However, tumour volumes overlapped between groups, indicating the need for multifactorial parameters as predictors. In addition, a complete local tumour response may be accompanied by residual disease in the regional lymph nodes.
authors.affiliation: Department of Surgery, Atrium Medical Center, Henri Dunantstraat 5, 6419 PC, Heerlen, The Netherlands.
authors.forename: Rachel L G M
authors.initials: RL
authors.lastname: Blom
authors.forename: Inge R
authors.initials: IR
authors.lastname: Steenbakkers
authors.forename: Guido
authors.initials: G
authors.lastname: Lammering
authors.forename: Roy F A
authors.initials: RF
authors.lastname: Vliegen
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Belgers
authors.forename: Charlotte
authors.initials: C
authors.lastname: de Jonge
authors.forename: Wendy M J
authors.initials: WM
authors.lastname: Schreurs
authors.forename: Marius
authors.initials: M
authors.lastname: Nap
authors.forename: Meindert N
authors.initials: MN
authors.lastname: Sosef
mesh_terms: D000328:Adult; D000368:Aged; D002277:Carcinoma / Q000000981:diagnostic imaging* / Q000473:pathology / Q000628:therapy; D059248:Chemoradiotherapy; D004938:Esophageal Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology / Q000628:therapy; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D020360:Neoadjuvant Therapy; D049268:Positron-Emission Tomography; D011237:Predictive Value of Tests; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome