Prognostic Value of 18F-FDG PET/CT in Surgical Non-Small Cell Lung Cancer: A Meta-Analysis

Abstract

Background: The identification of surgical non-small cell lung cancer (NSCLC) patients with poor prognosis is a priority in clinical oncology because of their high 5-year mortality. This meta-analysis explored the prognostic value of maximal standardized uptake value (SUVmax), metabolic tumor volume (MTV) and total lesion glycolysis (TLG) on disease-free survival (DFS) and overall survival (OS) in surgical NSCLC patients.

Materials and methods: MEDLINE, EMBASE and Cochrane Libraries were systematically searched until August 1, 2015. Prospective or retrospective studies that evaluated the prognostic roles of preoperative 18F-FDG PET/CT with complete DFS and OS data in surgical NSCLC patients were included. The impact of SUVmax, MTV or TLG on survival was measured using hazard ratios (HR). Sub-group analyses were performed based on disease stage, pathological classification, surgery only and cut-off values.

Results: Thirty-six studies comprised of 5807 patients were included. The combined HRs for DFS were 2.74 (95%CI 2.33-3.24, unadjusted) and 2.43 (95%CI: 1.76-3.36, adjusted) for SUVmax, 2.27 (95%CI 1.77-2.90, unadjusted) and 2.49 (95%CI 1.23-5.04, adjusted) for MTV, and 2.46 (95%CI 1.91-3.17, unadjusted) and 2.97 (95%CI 1.68-5.28, adjusted) for TLG. The pooled HRs for OS were 2.54 (95%CI 1.86-3.49, unadjusted) and 1.52 (95%CI 1.16-2.00, adjusted) for SUVmax, 2.07 (95%CI 1.16-3.69, unadjusted) and 1.91 (95%CI 1.13-3.22, adjusted) for MTV, and 2.47 (95%CI 1.38-4.43, unadjusted) and 1.94 (95%CI 1.12-3.33, adjusted) for TLG. Begg's test detected publication bias, the trim and fill procedure was performed, and similar HRs were obtained. The prognostic role of SUVmax, MTV and TLG remained similar in the sub-group analyses.

Conclusions: High values of SUVmax, MTV and TLG predicted a higher risk of recurrence or death in patients with surgical NSCLC. We suggest the use of FDG PET/CT to select patients who are at high risk of disease recurrence or death and may benefit from aggressive treatments.

Fig 1. Flowchart of Study Selection.

Fig 2. Forest plots of HR for recurrence with SUV_max (A, unadjusted; B, adjusted), MTV (C, unadjusted; D, adjusted) and TLG (E, unadjusted; F, adjusted).

The Chi² test is a measurement of heterogeneity. P<0.05 indicates significant heterogeneity. Squares = individual study point estimates. Horizontal lines = 95% CIs. Rhombus = summarized estimate and its 95% CI. Fixed: fixed effect model. Random: random effect model.

Fig 3. Funnel plots without (left column) and with (right column) trim and fill.

The pseudo 95% confidence interval (CI) is computed as part of the analysis that produced the funnel plot and corresponds to the expected 95% CI for a given standard error (SE). HR indicates hazard ratio.

Fig 4. Forest plots of HR for deaths with SUV_max (A, unadjusted; B, adjusted), MTV (C, unadjusted; D, adjusted) and TLG (E, unadjusted; F, adjusted).

The Chi² test is a measurement of heterogeneity. P<0.05 indicates significant heterogeneity. Squares = individual study point estimates. Horizontal lines = 95% CIs. Rhombus = summarized estimate and its 95%CI. Fixed: fixed effect model. Random: random effect model.