[Staging with 18F-FDG-PET/CT influences stage-specific survival in advanced non-small cell lung cancer (NSCLC)]

PET/CT investigation with 18F-fluorodeoxyglucose (FDG) has a high sensitivity (89 - 100 %) and good specificity (79 - 95 %) for the diagnosis of NSCLC. Currently, it is mainly used in preoperative staging. This leads in approximately 15 % of these cases to the diagnosis of metastatic disease that was neither clinically suspected nor seen in previously performed conventional imaging. We hypothesised that including these cases in the palliative stage IV group would have an influence on overall survival.

The aim of this study was to compare the overall survival (OS) of patients with stage IV NSCLC who underwent FDG-PET/CT staging with patients in whom conventional imaging procedures were performed.

We analysed the OS of all stage IV NSCLC patients diagnosed in our clinic in 2009 (n = 254), 96/254 (38 %) patients were staged with PET/CT and 158/254 (62 %) with conventional imaging (CT group). Survival data were compared by Kaplan-Meier statistics.

Patients in the PET/CT group were younger (65 ± 11) than in the CT group (68 ± 10 years; p = 0.008). The median OS of all patients was 246 (range: 217 - 275) days; 338 (range: 247 - 429) days in the PET/CT group and 207 (range: 161 - 253) days in the CT group (p = 0.001), stating a difference of 131 days (4.4 months) in median OS.

The use of FDG-PET/CT staging mainly in the preoperative setting leads to stage migration of patients with a better prognosis into the worst stage (IV) and thus longer survival within this subgroup. This survival benefit is unrelated to treatment and needs to be addressed in future studies.