title: The impact of 18-fluorodeoxyglucose positron emission tomography on the staging, management and outcome of anal cancer.
abstract: Accurate inguinal and pelvic nodal staging in anal cancer is important for the prognosis and planning of radiation fields. There is evidence for the role of 18-fluorodeoxyglucose positron emission tomography (FDG-PET) in the staging and management of cancer, with early reports of an increasing role in outcome prognostication in a number of tumours. We aimed to determine the effect of FDG-PET on the nodal staging, radiotherapy planning and prognostication of patients with primary anal cancer. Sixty-one consecutive patients with anal cancer who were referred to a tertiary centre between August 1997 and November 2005 were staged with conventional imaging (CIm) (including computed tomography (CT), magnetic resonance imaging, endoscopic ultrasound and chest X-ray) and by FDG-PET. The stage determined by CIm and the proposed management plan were prospectively recorded and changes in stage and management as a result of FDG-PET assessed. Patients were treated with a uniform radiotherapy technique and dose. The accuracy of changes and prognostication of FDG-PET were validated by subsequent clinical follow-up. Kaplan-Meier survival analysis was used to estimate survival for the whole cohort and by FDG-PET and CIm stage. The tumour-stage group was changed in 23% (14 out of 61) as a result of FDG-PET (15% up-staged, 8% down-staged). Fourteen percent of T1 patients (3 out of 22), 42% of T2 patients (10 out of 24) and 40% of T3-4 patients (6 out of 15) assessed using CIm, had a change in their nodal or metastatic stage following FDG-PET. Sensitivity for nodal regional disease by FDG-PET and CIm was 89% and 62%, respectively. The staging FDG-PET scan altered management intent in 3% (2 out of 61) and radiotherapy fields in 13% (8 out of 61). The estimated 5-year overall survival (OS) and progression-free survival (PFS) for the cohort were 77.3% (95% confidence interval (CI): 55.3-90.4%) and 72.2% (95% CI: 51.5-86.4%), respectively. The estimated 5-year PFS for FDG-PET and CIm staged N2-3 disease was 70% (95% CI: 42.8-87.9%) and 55.3% (95% CI: 23.3-83.4%), respectively. FDG-PET shows increased sensitivity over CIm for staging nodal disease in anal cancer and changes treatment intent or radiotherapy prescription in a significant proportion of patients.
authors.affiliation: Department of Oncology, Royal United Hospital, Bath, UK.
authors.forename: E de
authors.initials: Ed
authors.lastname: Winton
authors.forename: A G
authors.initials: AG
authors.lastname: Heriot
authors.forename: M
authors.initials: M
authors.lastname: Ng
authors.forename: R J
authors.initials: RJ
authors.lastname: Hicks
authors.forename: A
authors.initials: A
authors.lastname: Hogg
authors.forename: A
authors.initials: A
authors.lastname: Milner
authors.forename: T
authors.initials: T
authors.lastname: Leong
authors.forename: M
authors.initials: M
authors.lastname: Fay
authors.forename: J
authors.initials: J
authors.lastname: MacKay
authors.forename: E
authors.initials: E
authors.lastname: Drummond
authors.forename: S Y
authors.initials: SY
authors.lastname: Ngan
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001005:Anus Neoplasms / Q000175:diagnosis* / Q000473:pathology / Q000628:therapy*; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis* / Q000473:pathology / Q000628:therapy*; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D049268:Positron-Emission Tomography / Q000379:methods*; D011379:Prognosis; D012680:Sensitivity and Specificity
chemical_list: D019788:Fluorodeoxyglucose F18