The aims were to determine if the maximum standardized uptake value (SUV max) of the primary tumor as determined by preoperative 18F-fluoro-2-deoxyglucose ( 18F-FDG) positron emission tomography (PET) is an independent predictor of overall survival and to assess its prognostic value after stratification according to pathological staging.
A retrospective clinicopathologic review of 363 patients who had a preoperative 18F-FDG PET done before undergoing attempted curative resection for early-stage (I & II) non-small cell lung cancer (NSCLC) was performed. Patients who had received any adjuvant or neoadjuvant chemotherapy or radiation therapy were excluded. The primary outcome measure was duration of overall survival. Receiver-operating characteristic (ROC) curves were plotted to find out the optimal cutoff values of SUV max yielding the maximal sensitivity plus specificity for predicting the overall survival. Survival curves stratified by median SUV max and optimal cutoff SUV max were estimated by the Kaplan-Meier method and statistical differences were assessed using the log-rank test. Multivariate proportional hazards (Cox) regression analyses were applied to test the SUV max’s independency of other prognostic factors for the prediction of overall survival.
The median duration of follow-up was 981 days (2.7 years). The median SUV max was 5.9 for all subjects, 4.5 for stage IA, 8.4 for stage IB, and 10.9 for stage IIB. The optimal cutoff SUV max was 8.2 for all subjects. No optimal cutoff could be established for specific stages. In univariate analyses, each doubling of SUV max [i.e., each log (base 2) unit increase in SUV max] was associated with a 1.28-fold [95% confidence interval (CI): 1.03–1.59, p = 0.029] increase in hazard of death. Univariate analyses did not show any significant difference in survival by SUV max when data were stratified according to pathological stage ( p = 0.119, p = 0.818, and p = 0.882 for stages IA, IB, and IIB, respectively). Multivariate analyses demonstrated that SUV max was not an independent predictor of overall survival ( p > 0.05).