Usefulness of fluoro-2-deoxyglucose positron emission tomography for investigating unexplained rising carcinoembryonic antigen levels that occur during the postoperative surveillance of lung cancer patients.

BACKGROUND

Positron emission tomography with 18-fluorodeoxyglucose (FDG-PET) has been useful for the detection of recurrent lung cancer. However, such technology is expensive and is not always widely available. In this study, we evaluated the selected use of FDG-PET for lung cancer patients with re-elevated levels of serum carcinoembryonic antigen (CEA) after curative surgery.

METHODS

Among 327 patients who underwent curative resection for primary lung cancer from May 2002 through March 2007, 199 had adenocarcinoma, of whom 78 (39%) had elevated levels of serum CEA before treatment. After surgery, the level was monitored every 1 to 3 months. Re-elevation of CEA was recognized in 39 (50%) patients, 22 of whom underwent FDG-PET and were included in this study. FDG-PET images were visually inspected, and abnormally increased FDG uptake was interpreted as recurrence. The sensitivity, specificity, positive predictive value, and negative predictive value of PET in detecting recurrent lung cancer were determined.

RESULTS

FDG-PET correctly identified 14 out of 15 relapses and gave true negative results in six out of seven remissions, i.e., one false-negative and one false-positive were observed. The sensitivity, specificity, positive predictive value, and negative predictive value were 93%, 86%, 93%, and 86%, respectively.

CONCLUSION

In 64% of the patients with unexplained increased CEA levels, FDG-PET provided decisive diagnostic clues guiding further diagnostic and therapeutic interventions. The selected use of FDG-PET for patients with re-elevated serum CEA levels after surgery can be a practical and effective mode of surveillance for detecting recurrent lung cancer.