Impact of routine preoperative 18 FDG PET/CT on the surgical management of primary colorectal cancer.

OBJECTIVES: Determine the usefulness of [18F]-fluorodeoxyglucose positron emission tomography/computed tomography (18 FDG-PET/CT) in the preoperative setting of colorectal cancer (CRC), assessing its impact on changes in management strategy.

METHODS: Retrospective study of CRC patients who underwent preoperative 18 FDG-PET/CT and CT staging scans in a single referral center. The agreement between 18 FDG-PET/CT, contrast-enhanced CT, and colonoscopy for the surgical location was compared using the κ coefficient. Maximum standardized uptake (SUVmax ) value was obtained. Univariate and multivariate analyses were conducted.

RESULTS: One hundred ninety-five patients were included. 18 FDG-PET/CT improved tumor localization in 84.6% (165/195) of cases (κ value 0.798, p < 0.001), thus correcting endoscopic errors 69.7% (30/43) of the time. In patients with incomplete colonoscopies, 18 FDG-PET/CT detected synchronous tumors in 2.5% (5/195) patients, overlooked by CT staging scans. Based on extracolonic 18 FDG-uptake, the second primary malignancy was diagnosed in 7(3.6%,7/195) patients and total accuracy for lymph node and distant metastasis was 66.1% and 98.4%, respectively. The treatment plan was altered in 30 (15.4%, 30/196) patients. There was a significant association between the SUVmax and tumor size (odds ratio [OR] 4.254, p = 0.003) and the depth of tumor invasion (OR 1.696, p = 0.026).

CONCLUSIONS: Based on its ability to aid in preoperative evaluation and definitively alter surgical treatment planning, 18 FDG-PET/CT should be further evaluated in primary CRC.