Revisiting the prognostic value of preoperative (18)F-fluoro-2-deoxyglucose ( (18)F-FDG) positron emission tomography (PET) in early-stage (I & II) non-small cell lung cancers (NSCLC)

Abstract

Purpose: The aims were to determine if the maximum standardized uptake value (SUV(max)) of the primary tumor as determined by preoperative (18)F-fluoro-2-deoxyglucose ((18)F-FDG) positron emission tomography (PET) is an independent predictor of overall survival and to assess its prognostic value after stratification according to pathological staging.

Methods: A retrospective clinicopathologic review of 363 patients who had a preoperative (18)F-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.

Results: 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).

Conclusion: Each doubling of SUV(max) as determined by preoperative PET is associated with a 1.28-fold increase in hazard of death in early-stage (I & II) NSCLC. Preoperative SUV(max) is not an independent predictor of overall survival.

Fig. 1

Frequency distribution of SUV_max

Fig. 2

Kaplan-Meier survival curves by median SUV_max (5.9) in all subjects (log-rank p = 0.018)

Fig. 3

Kaplan-Meier survival curves by optimal cutoff SUV_max (8.2) in all subjects (log-rank p = 0.004)

Fig. 4

Effects of partial volume

Fig. 5

Kaplan-Meier survival curves by median SUV_max (4.5) in stage IA patients (log-rank p = 0.071)

Fig. 6

Kaplan-Meier survival curves by median SUV_max (8.4) in stage IB patients (log-rank p = 0.682)

Fig. 7

Kaplan-Meier survival curves by median SUV_max (10.85) in stage IIB patients (log-rank p = 0.928)