title: FDG-PET metabolic response predicts outcomes in anal cancer managed with chemoradiotherapy.
abstract: BACKGROUND
  The aim was to investigate the correlation between (18)F-fluorodeoxyglucose positron emission tomography (FDG-PET) metabolic response to chemoradiotherapy and clinical outcomes in squamous cell carcinoma (SCC) of the anus.
  
  
  METHODS
  A total of 48 patients with biopsy-proven anal SCC underwent FDG-PET scans at baseline and post chemoradiotherapy (54 Gy, concurrent 5-FU/mitomycin). Kaplan-Meier analysis was used to determine survival outcomes according to FDG-PET metabolic response.
  
  
  RESULTS
  In all, 79% patients (n=38) had a complete metabolic response (CMR) at all sites of disease, 15% (n=7) had a CMR in regional nodes but only partial response in the primary tumour (overall partial metabolic response (PMR)) and 6% (n=3) had progressive distant disease despite CMR locoregionally (overall no response (NR)). The 2-year progression-free survival (PFS) was 95% for patients with a CMR, 71% for PMR and 0% for NR (P<0.0001). The 5-year overall survival (OS) was 88% in CMR, 69% in PMR and 0% in NR (P<0.0001). Cox proportional hazards regression analyses for PFS and OS found significant associations for incomplete (PMR+NR) vs complete FDG-PET response to treatment only, (HR 4.1 (95% CI: 1.5-11.5, P=0.013) and 6.7 (95% CI: 2.1-21.6, P=0.002), respectively).
  
  
  CONCLUSIONS
  FDG-PET metabolic response to chemoradiotherapy in anal cancer is significantly associated with PFS and OS, and in this cohort incomplete FDG-PET response was a stronger predictor than T or N stage.
authors.affiliation: Department of Haematology and Medical Oncology, Peter MacCallum Cancer Centre, Locked Bag 1, A'Beckett Street, Melbourne, 8006, Victoria, Australia.
authors.forename: F L
authors.initials: FL
authors.lastname: Day
authors.forename: E
authors.initials: E
authors.lastname: Link
authors.forename: S
authors.initials: S
authors.lastname: Ngan
authors.forename: T
authors.initials: T
authors.lastname: Leong
authors.forename: K
authors.initials: K
authors.lastname: Moodie
authors.forename: C
authors.initials: C
authors.lastname: Lynch
authors.forename: M
authors.initials: M
authors.lastname: Michael
authors.forename: E de
authors.initials: Ed
authors.lastname: Winton
authors.forename: A
authors.initials: A
authors.lastname: Hogg
authors.forename: R J
authors.initials: RJ
authors.lastname: Hicks
authors.forename: A
authors.initials: A
authors.lastname: Heriot
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D001005:Anus Neoplasms / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000378:metabolism / Q000401:mortality / Q000532:radiotherapy*; D001315:Australia / Q000453:epidemiology; D002294:Carcinoma, Squamous Cell / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000378:metabolism / Q000401:mortality / Q000532:radiotherapy*; D017024:Chemotherapy, Adjuvant; D015986:Confounding Factors, Epidemiologic; D018572:Disease-Free Survival; D019583:Dose Fractionation, Radiation; D005260:Female; D019788:Fluorodeoxyglucose F18 / Q000378:metabolism*; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography / Q000379:methods; D016016:Proportional Hazards Models; D019275:Radiopharmaceuticals / Q000378:metabolism; D018714:Radiotherapy, Adjuvant; D012189:Retrospective Studies; D016896:Treatment Outcome
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18