Diagnostic accuracy of 18F-FDG PET/CT scan in distant metastasis staging of non-small cell lung cancer: A meta-analysis.

BACKGROUND

Accurate detection of distant metastasis (M stage) is pivotal in treatment planning for non-small cell lung cancer (NSCLC). 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) combines metabolic and anatomic information and may outperform conventional imaging for baseline M-staging. Hence, this review was done to determine the diagnostic accuracy of 18F-FDG PET/CT for distant metastasis of NSCLC.

METHODS

Following Preferred Reporting Items for Systematic Review and Meta-Analysis-Diagnostic Test Accuracy, we included studies of adults with NSCLC that reported per-patient diagnostic accuracy of 18F-FDG PET/CT for any distant metastasis against histology and/or composite reference standard. Two reviewers independently screened, extracted data, and appraised risk of bias with Quality Assessment of Diagnostic Accuracy Studies-2. Summary sensitivity and specificity were pooled using a bivariate random-effects model with summary receiver operator characteristics curve and likelihood ratios (LRs); heterogeneity, threshold effects, and small-study bias (Deeks test) were assessed.

RESULTS

Fifteen studies (298 reference-positive, 1915 reference-negative; pretest probability 13%) were included. Pooled sensitivity and specificity were 0.91 (95% confidence interval: 0.70-0.98) and 0.98 (0.96-0.99), area under the receiver operating characteristic 0.99 (0.97-0.99). LR+ and LR- were 39.0 (21.5-70.8) and 0.09 (0.02-0.35), respectively; heterogeneity was substantial (I2 = 87%). Deeks test showed no asymmetry (P = .48). With contrast-enhanced computed tomography (8 studies), sensitivity and specificity were 0.99 (0.86-1.00) and 0.98 (0.95-0.99), area under the receiver operating characteristic 1.00, with negligible heterogeneity.

CONCLUSION

18F-FDG PET/CT provides substantial discrimination for distant metastasis in NSCLC, strongly informing treatment intent. Incorporating diagnostic contrast-enhanced computed tomography within PET/CT materially improves and stabilizes sensitivity; non-contrast protocols retain rule-in value but are less reliable to rule out metastasis.