The prognostic significance of SUV_max on ¹⁸F-FDG PET/CT in early-staged non-small cell lung cancer after SBRT: a meta-analysis

Objectives Stereotactic body radiotherapy (SBRT) or stereotactic ablative radiation therapy (SABR) is becoming the standard treatment for early-staged non-small cell lung cancer (NSCLC) patients who are ineligible for surgery. The prognostic importance of ¹⁸F-FDG PET standardized uptake value maximum (SUV_max) scores for NSCLCs receiving SBRT was not well defined. The purpose of meta-analysis is to evaluate the efficacy of SUVmax on ¹⁸F-FDG PET imaging to predict prognosis and exact survival receiving SBRT.

Methods All published English-language studies were collected in the EMBASE and MEDLINE databases . All the studies were published from January 2000 to January 2014 and limited to NSCLC,PET/CT, SBRT, the impact of SUV_max on survival.The necessary data for calculation of individual hazard ratios (HRs) were drawn from each study. A random-effects model was used to observe heterogeneity. The substantial heterogeneity was defined as an I²＞50%. The results were verified and examined by two reviewers independently .

Results After assessment of original articles, patients (n = 1018) from 11 retrospective studies were evaluable . Eight studies were included for OS analysis with 820 patients. The combined HR was 1.04(95%CI: 0.95~1.12, p=0.40) with heterogeneity (I²=0%). Six studies were included for local control analysis with 526 patients. The combined HR was 1.05 (95% CI: 1.01~1.08) with heterogeneity (I²=49%). A forest plot attributed most of the heterogeneity to one study. After excluding this article, the heterogeneity was reduced to 19% and the combined HR was 1.05 (95% CI:1.02~1.08, p=0.006).

Conclusions This meta-analysis found a correlation of high SUV_max of primary tumor with poor local control in stage I NSCLC patients receiving SBRT, but could not predict the outcome of overall survival. Further individual data based analysis and perspective studies are warranted to confirm the prognosis value of pretreatment FDG uptake in early-staged NSCLC receiving SBRT and investigate the feasible of PET/CT images guiding individualized treatments.