Prognostic implication of dual-phase PET in adenocarcinoma of the lung

The purpose of this study was to determine whether dual-phase (18)F-FDG PET could be a prognostic factor for adenocarcinoma of the lung.

One hundred patients with histologically proven adenocarcinoma of the lung were included in this retrospective analysis. All patients underwent dual-phase pretherapy (18)F-FDG PET for which, after the intravenous administration of (18)F-FDG, both early (approximately 60 min) and delayed (approximately 90 min) PET were acquired. The percentage change in the maximal standardized uptake values (SUVmax) of the cancer between the early and the delayed images was calculated. Overall survival of the SUVmax change over time together with the known prognostic factors were calculated by the Kaplan-Meier method and evaluated with the log-rank test. The prognostic significance was assessed by univariate and multivariate analyses.

Statistical analysis showed that SUVmax change over time between the early and the delayed PET was a strong independent predictor of outcome for lung adenocarcinoma. A cutoff of 25% change for SUVmax over time showed the best discriminative value. Patients with more than 25% increase in SUVmax had a median survival of 15 mo, compared with 39 mo for those with less than 25% increase in SUVmax.

Dual-phase (18)F-FDG PET reflects the dynamics of glucose metabolism. Our findings suggest that the percentage SUVmax change over time is a strong prognostic factor in patients with lung adenocarcinoma and can be complementary to the other well-known factors.