Utility of 18‐fluorodeoxyglucose positron emission/computed tomography in the management of recurrent colorectal cancer

Background This study aimed to evaluate the utility of 18‐fluorodeoxyglucose positron emission/computed tomography ( PET / CT ) in the management of colorectal cancer ( CRC ) patients with suspected recurrence. Methods Clinical and imaging histories of CRC patients who underwent PET / CT at our institution between 1 A pril 2007 and 31 A ugust 2008 for evaluation of recurrent disease were retrospectively reviewed. Patients were divided into two groups – (A) patients evaluated for suspected local recurrence (based on conventional imaging) and (B) patients with carcinoembryonic antigen ( CEA) levels in excess of 5 ng/mL; in whom conventional imaging was either normal or equivocal. Sensitivity, specificity, positive predictive value ( PPV ) and negative predictive value ( NPV ) were derived using either histopathology or follow‐up imaging as the standard of reference. Results In group A ( n = 44), the sensitivity, specificity, PPV , NPV and accuracy of PET / CT were 100% (95% confidence interval ( CI): 86.7–100), 84.2% (95% CI: 62.4–94.5), 89.3% (95% CI: 72.8–96.3), 100% (95% CI: 80.6–100) and 93.2%, respectively. In group B ( n = 18), the sensitivity, specificity, PPV and NPV of PET / CT were 76.9% (95% CI: 49.7–91.8), 60.0%, (95% CI: 23.1–88.2), 83.3% (95% CI: 55.2–95.3) and 50% (95% CI: 18.8–81.2), respectively. Conclusion PET / CT has high accuracy in the assessment of local recurrence, particularly with regard to its NPV . PET / CT is useful for problem solving in cases of unexplained elevated CEA levels.