T1 lung cancers: sensitivity of diagnosis with fluorodeoxyglucose PET.

PURPOSE: To determine the sensitivity of fluorodeoxyglucose (FDG) positron emission tomography (PET) in patients with T1 (< or =3 cm) lung cancers.

MATERIALS AND METHODS: One hundred eighty-five patients with 192 histopathologically proved T1 lung cancers underwent FDG PET imaging at the time of diagnosis. PET results were correlated with tumor size, histopathologic findings, and patient outcome by using the two-sample t test, exact chi(2) test, and log rank test, respectively.

RESULTS: Of the 192 lesions, 183 (95%) that ranged in size from 0.5 to 3.0 cm in diameter (mean, 2.0 cm) were positive at PET (ie, demonstrated increased FDG uptake). Of the 192 lesions, nine (5%) that ranged in size from 0.3 to 2.5 cm in diameter (mean, 1.3 cm) were negative at PET (ie, demonstrated low FDG uptake). Patients with small tumors, as well as those with carcinoid tumors and bronchioloalveolar cell carcinoma, were more likely to have a negative PET scan (P =.004, P =.003, respectively). In addition, patients with a negative PET scan who subsequently proved to have cancer had significantly longer survival than did patients with a positive scan and cancer (P =.043).

CONCLUSION: Most T1 lung cancers show increased FDG uptake on PET scans.