Is FDG-PET/CT used correctly in the combined approach for nodal staging in NSCLC patients?

Predictive value of 18F-FDG PET/CT metabolic parameters for lymph node metastasis of non-small cell lung cancer

BACKGROUND

Lymph node metastasis is closely associated with the prognosis of patients with non-small cell lung cancer (NSCLC). This study aimed to evaluate the role of preoperative 18F-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) parameters in mediastinal lymph node metastasis in NSCLC.

METHODS

One hundred patients with NSCLC who underwent surgery, systematic lymph node dissection, who had undergone 18FFDG PET/CT for initial staging were divided into two groups: lymph node metastasis and non-metastasis. The maximum standardized uptake value (SUVmax), average standardized uptake value (SUVmean), SUV in the liver (SURliver), mediastinal blood pool (SURblood), metabolic tumor volume (MTV), and total lesion glycolysis (TLG) were detected in both groups. Receiver operating characteristic (ROC) curves were used to evaluate the parameters for predicting the diagnostic efficacy.

RESULTS

The SUVmax, SUVmean, SURblood, SURliver, MTV, and TLG were higher in the group with lymph node metastasis than in the group without lymph node metastasis. The ROC analysis showed that 18F-FDG PET/CT demonstrated acceptable predictive ability with AUC of 0.964 (95% CI, 0.930-0.998).

CONCLUSIONS

The relative 18F-FDG PET/CT primary uptake and substitution parameters showed acceptable predictive efficacy for mediastinal lymph node metastasis in patients with NSCLC. Additional, SURblood has potential for clinical application.

The diagnostic value of metabolic, morphological and heterogeneous parameters of 18F-FDG PET/CT in mediastinal lymph node metastasis of non-small cell lung cancer

OBJECTIVES

To investigate the value of PET/CT metabolic, morphological and heterogeneous parameters in the diagnosis of 18F-FDG positive mediastinal lymph node metastasis in non-small cell lung cancer (NSCLC).

PATIENTS AND METHODS

A total of 156 patients with pathologically diagnosed NSCLC and underwent 18F-FDG PET/CT scans were enrolled in this study. Mediastinal lymph nodes with 18F-FDG uptake greater than the mediastinum were analyzed. The metabolic parameters of maximum and mean standardized uptake value (SUVmax, SUVmean), SUVratio (node SUVmax/mediastinum SUVmax), metabolic tumor volume (MTV), total lesion glycolysis (TLG), morphological parameters of maximum short diameter (Dmin), CT values and metabolic heterogeneity parameter of coefficient of variation (COV) were measured. The performance of each parameter and their combinations for diagnosis of lymph node metastasis was evaluated through receiver operating characteristic (ROC) curves and binary logistic regression analysis.

RESULTS

There were 206 lymph nodes with pathological evidence included in the study, including 103 metastatic and 103 nonmetastatic nodes. The SUVmax, SUVmean, SUVratio, TLG, COV and Dmin of metastatic lymph nodes were significantly higher/greater than those in nonmetastatic ones (P < 0.05). ROC curve analysis revealed that the combination of SUVratio, Dmin and COV showed the highest diagnostic efficacy among all single and combined parameters, the area under the curve (AUC) was 0.907 (P = 0.000), these three parameters all increased the risk of lymph node metastasis, with odds ratios of 1.848, 1.293 and 1.258, respectively (all P < 0.05).

CONCLUSION

Heterogeneity parameter was helpful for the accurate distinction of mediastinal lymph node metastasis in NSCLC. The combination of the SUVratio, Dmin and COV could improve the diagnostic accuracy. Multiple-parameters analysis plays an important complementary role in the diagnosis of lymph node metastasis.