title: Should aggressive thoracic therapy be performed in patients with synchronous oligometastatic non-small cell lung cancer? A meta-analysis.
abstract: BACKGROUND
  We performed a meta-analysis to compare overall survival (OS) outcomes in patients with synchronous oligometastatic non-small cell lung cancer (NSCLC) who underwent aggressive thoracic therapy (ATT) with those who did not.
  
  
  METHODS
  A systematic review of controlled trials of ATT on survival in synchronous oligometastatic NSCLC was conducted. Hazard ratio (HR) for the main endpoint OS was pooled using a fixed-effects model. Subgroup analysis was performed in patients with single organ metastases, or with different numbers of brain metastases, or with different stages of thoracic disease. Pooled survival curves of OS were constructed.
  
  
  RESULTS
  Seven eligible retrospective observational cohort studies were identified including 668 synchronous oligometastatic NSCLC patients, of whom 227 (34.0%) received ATT. For patients with synchronous oligometastatic NSCLC, ATT was associated with a significant improvement of OS (HR, 0.48; 95% CI, 0.39-0.60; P<0.00001). In subgroup analysis, the association with OS was similar or even strengthened, with a HR of 0.42 (95% CI, 0.31-0.56) in single organ metastases group, 0.49 (95% CI, 0.31-0.75) in solitary brain metastasis group, and 0.38 (95% CI, 0.20-0.73) in thoracic stage I-II group, respectively. The pooled cumulative survival rates for patients received ATT were 74.9% at 1 year, 52.1% at 2 years, 23.0% at 3 years, and 12.6% at 4 years. The corresponding pooled survival for patients who did not receive ATT were 32.3%, 13.7%, 3.7%, and 2.0%, respectively.
  
  
  CONCLUSIONS
  Survival benefit from ATT is common in synchronous oligometastatic patients. Selected patients with synchronous oligometastatic NSCLC could also achieve long-term survival with ATT.
authors.affiliation: Department of Radiation Oncology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China.
authors.forename: Dianhe
authors.initials: D
authors.lastname: Li
authors.affiliation: Department of Radiation Oncology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China.
authors.forename: Xiaoxia
authors.initials: X
authors.lastname: Zhu
authors.affiliation: Department of Cardiothoracic Surgery, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China.
authors.forename: Haofei
authors.initials: H
authors.lastname: Wang
authors.affiliation: School of Public Health and Tropical Medicine, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China.
authors.forename: Min
authors.initials: M
authors.lastname: Qiu
authors.affiliation: Department of Radiation Oncology, Nanfang Hospital, Southern Medical University, Guangzhou 510515, China.
authors.forename: Na
authors.initials: N
authors.lastname: Li
keywords: Synchronous oligometastases; aggressive thoracic therapy (ATT); meta-analysis; non-small cell lung cancer (NSCLC); overall survival (OS)