Comparison of preoperative whole-body positron emission tomography with MDCT in patients with primary colorectal cancer

Preoperative use of emission tomography with(18)F-fluorodeoxyglucose (FDG-PET) in patients with primary colorectal cancer remains controversial. This study evaluated the additional value of FDG-PET in comparison with routine multidetector row computed tomography (MDCT) in patients with primary colorectal cancer. Retrospective analysis was performed in 65 patients with colorectal cancer who underwent whole-body FDG-PET. Results of FDG-PET were compared with routine preoperative evaluation by MDCT regarding detection of primary tumour, lymph node involvement and distant metastases. All images were evaluated before surgery. Tumour detection rate was 100% (63/63) for MDCT and 98% (62/63) for FDG-PET. Lymph node involvement was pathologically confirmed in 35 patients. MDCT and FDG-PET displayed sensitivities of 89% (31/35; 95% CI: 73-97%) and 43% (15/35; 95% CI: 26-61%) and specificities of 52% (11/21; 95% CI: 30-74%) and 95% (20/21; 95% CI: 76-100%), respectively. Liver metastases were present in 22 patients. MDCT and FDG-PET showed accuracies of 98% (64/65; 95% CI: 92-100%) and 97% (63/65; 95% CI: 89-100%), respectively. FDG-PET detected additional extrahepatic metastatic lesions and affected treatment plan compared with MDCT in 10 patients. Preoperative FDG-PET is not superior to MDCT for detection of primary tumour, lymph node involvement or liver metastases, but may have potential clinical value in patients with advanced colorectal cancer by detecting extrahepatic distant metastases.