DETECTING RECURRENT OR RESIDUAL LUNG-CANCER WITH FDG-PET

We investigated the diagnostic accuracy of FDG-PET in the detection of recurrent lung cancer. Methods: Thirty-nine lesions in 38 patients wi th clinically suspected recurrent or residual lung cancer were studied with PET. All PET images were visually interpreted in conjunction wit h thoracic CT or MRI. Semiquatititative analysis using standardized up take values (SUVs) was also performed in 25 lesions. FDG-PET diagnoses were correlated with pathological diagnoses and clinical outcome. Res ults: The sensitivity and specificity of FDG-PET for detecting recurre nt tumors were 100% (26/26) and 61.5% (8/13), respectively. The differ ence in mean SUV between recurrent tumors and noncancerous lesions was statistically significant [11.2 +/- 5.7 (n = 16)vs. 3.5 +/- 1.8 (n = 9), p < 0.0001]. False-positive results showed relatively lower SUVs t han true-positives and also demonstrated increased uptake in a curvili near rather than nodular shape. Conclusion: FDG-PET is useful for dete cting recurrent lung cancer after treatment. False-positive diagnoses might be reduced by analysis of uptake shape and serial changes in SUV , but further study is needed.