Significance of PET/CT in determining actual TNM staging for patients with various lung cancers.

We investigated the difference in TNM stage of lung cancer provided by PET/CT (combining positron emission tomography and computed tomography) as compared with TNM stage obtained with conventional imaging studies (CI) with contrast-enhanced computed tomography (CT) and magnetic resonance imaging (MRI) with iron contrast media. Sixty-seven cases of lung cancer were included in this study. Overall, the rate of correction of TNM staging was 70.1% after PET/CT. The correction rate for each factor was 32.8% in T, 37.3% in N, and 37.3% in M. High rates of correction were observed in small cell lung cancer (SCLC), with 75% (6/8 cases) obtained by PET/CT. When SCLCs were divided into limited disease (n = 6) involving 1 hemithorax, including mediastinal and contralateral hilar lymph nodes, and others (extensive disease, n = 2), the correction rate was as high as 80% for limited disease. In conclusion, PET/CT can provide actual TNM staging and recognition for oncologists in staging, which would not mislead to selection of inadequate subsequent treatment.