18-F-Fdg Pet, Pet/Ct And Mdct In Locally Advanced Colorectal Cancer

The aim of our study was to assess contrast enhanced multi-detector CT (CE-MDCT), FDG-PET and FDG-PET/CT accuracy in loco-regional staging of colorectal cancer. Methods: Eighteen (10 M, 8 F; aged 41-77 years) patients with histologically proven colorectal adenocarcinoma were enrolled. All patients underwent surgical resection within ten days of diagnostic assessment. CE-MDCT, FDG-PET and FDG-PET/CT were reviewed without knowledge of the results of histology. For each primary lesion a 3 point scale for characterization (1=benign, 2=indefinite, 3=malignant) and localization (1=uncertain, 2=probable, 3=certain) was used for FDG-PET and FDG-PET/CT. Sensitivity, specificity and accuracy were assessed for T staging for CE-MDCT and for N staging for CE-MDCT, FDG-PET and FDG-PET/CT. Results: 19 adenocarcinomas were identified at surgery (one patients had two synchronous lesions). Both CE-MDCT and FDG-PET/CT correctly identified and localized all lesions, while FDG-PEt alone identified all lesions, but only 14 of them (74%) were correctly localized. T stage was correctly identified by CE-MDCT in 17/19 lesions (90%). CE-MDCT correctly staged N parameter in 12/19 lesions (63%). On the other hand, FDG-PET correctly staged N parameter in 11/19 (58%) lesions, while FDG-PET/CT correctly staged N parameter in 16/19 (84%, p<0.05 vs PET) lesions. Overall, FDG-PET/CT showed higher sensitivity than FDG-PET and higher specificity than CE-MDCT in evaluating lymph-node involvement (p<0.05). Conclusion: These data suggest that fused FDG-PET/CT increases the accuracy of FDG-PET in localization of primary lesion and of both MDCT and FDG-PET in loco-regional N staging in patients with colon-rectal cancer.