CR13UTILITY OF 18-FLUORODEOXYGLUCOSE POSITRON EMISSION TOMOGRAPHY (FDG-PET) IN THE STAGING AND MANAGEMENT OF ANAL CANCER

Accurate nodal staging in anal cancer is important for prognosis and planning of chemo-radiation fields. Mounting evidence exists for FDG-PET in the staging and management of cancer, with superior sensitivity and specificity compared to conventional imaging (CI) shown for several tumour sites, although little published data for anal cancer. The aim of the study was to determine the impact of FDG-PET on the nodal staging and management of patients with primary anal cancer. Sixty-two consecutive patients with anal cancer referred to a tertiary centre between August 1997 and November 2005 were staged with CI and FDG-PET. The stage determined by CI and the proposed management plan was prospectively recorded prior to FDG-PET. The impact of FDG-PET on stage and management was assessed and the accuracy of changes confirmed by subsequent clinical follow-up. The stage was changed in 23% (14/62) as a result of FDG-PET (15% up-staged, 8% down-staged). The staging FDG-PET scan had high impact (altering management intent) in 3% (2/62), and medium impact (altering radiotherapy fields) in 13% (8/62). Fourteen percent of T1 patients (3/22), 42% of T2 patients (10/24) and 38% of T3-4 patients (6/16), assessed using CI, had a change in their N or M stage following FDG-PET. Sensitivity for nodal disease for CI and FDG-PET was 72% and 92% and specificity was 99.5% and 100% respectively. FDG-PET shows increased sensitivity over CI for staging nodal disease in anal cancer and changes management in a significant proportion of patients. [PUBLICATION ABSTRACT]