title: Role of gross tumor volume in the prognosis of non-small cell lung cancer treated with 3D conformal radiotherapy: a meta-analysis.
abstract: OBJECTIVE
  Three-dimensional conformal radiotherapy (3D-CRT) has become widely applied in patients with non-small cell lung cancer (NSCLC), and gross tumor volume (GTV) is a reliable index for predicting prognosis in patients with NSCLC. This meta-analysis investigated the association between GTV and prognosis in patients with NSCLC after 3D-CRT.
  
  
  METHODS
  Electronic bibliographic databases were searched to identify articles related to NSCLC and 3D-CRT. The search results were carefully screened, using predetermined selection criteria, to select the most relevant studies. Newcastle-Ottawa Scale criteria were applied by 2 reviewers independently to evaluate the quality of the methodology of each included article., Based on GTV, each patient was assigned to either the study group (large GTV [≥112 cm(3)]) or the control group (small GTV [<112 cm(3)]), and the mean rates of overall survival (OS) and survival at 1, 3, and 5 years were calculated in each group. Summary hazard ratio (HR) with 95% CI was calculated.
  
  
  RESULTS
  The data from 10 cohort studies were incorporated into the current meta-analysis (1473 patients; study group, 773; control group, 700). The OS in the study group was significantly less than that in the control group (HR = 1.52; 95% CI, 1.10-1.94; P < 0.01). The study and control groups also had significantly different survival rates at 1 year (HR = 1.27; 95% CI, 1.10-1.46, P = 0.01), 3 years (HR = 2.06; 95% CI, 1.63-2.61; P < 0.01), and 5 years (HR = 2.25; 95% CI, 1.63-3.10; P < 0.01). Findings from funnel plots and Egger tests of the OS and 3-year survival rate suggested no publication bias. With respect to the 1- and 5-year survival rates, however, the funnel plots and Egger tests demonstrated publication bias among the included studies.
  
  
  CONCLUSIONS
  The relatively small number of studies and small sample size, as well as the lack of a specific and standard method of defining small and large GTV, may have influenced the credibility and reliability of our results. The findings suggest that GTV influences prognosis in patients with NSCLC after 3D-CRT. However, further studies with larger sample sizes are needed to confirm our finding that a larger GTV is negatively associated with NSCLC prognosis after 3D-CRT.
authors: Department of Radiation Oncology, Shandong's Key Laboratory of Radiation Oncology.
authors: Yang
authors: Y
authors: Yu
authors: Department of Radiation Oncology, Shandong's Key Laboratory of Radiation Oncology.
authors: Hui
authors: H
authors: Guan
authors: Department of Oncology, Shandong Cancer Hospital and Institute, School of Medicine and Life Sciences, University of Jinan and Shandong Academy of Medical Sciences, Jinan. Electronic address: xingligang_gmrkj@126.com.
authors: Li-Gang
authors: LG
authors: Xing
authors: Department of Oncology, Renji Hospital, Shanghai Jiao Tong University, Shanghai, People's Republic of China.
authors: Yong-Bing
authors: YB
authors: Xiang
mesh_terms: D002289:Carcinoma, Non-Small-Cell Lung / Q000401:mortality / Q000473:pathology* / Q000532:radiotherapy*; D015331:Cohort Studies; D006801:Humans; D008175:Lung Neoplasms / Q000401:mortality / Q000473:pathology* / Q000532:radiotherapy*; D011379:Prognosis; D016016:Proportional Hazards Models; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal; D015203:Reproducibility of Results; D012189:Retrospective Studies; D015996:Survival Rate; D047368:Tumor Burden
keywords: 3D conformal radiotherapy; gross tumor volume; meta-analysis; non–small cell lung cancer