title: Prognostic factors for resection of isolated pulmonary metastases in breast cancer patients: a systematic review and meta-analysis.
abstract: BACKGROUND
  Lung is a common organ of metastases in patients with primary breast cancer. Pulmonary metastasis of primary breast cancer is usually considered as a systemic disease, however, the systemic approaches have achieved little progress in terms of prolonging survival time. In contrast, some studies revealed a probable survival benefit of pulmonary metastasectomy for such patients. However, the prognostic factor for pulmonary metastasectomy in breast cancer patients is still a controversial issue. The aim of this study was to conduct a systematic review and meta-analysis of cohort studies to assess the pooled 5-year overall survival (OS) rate and the prognostic factors for pulmonary metastasectomy from breast cancer.
  
  
  METHODS
  An electronic search in MEDLINE (via PubMed), EMBASE (via OVID), CENTRAL (via Cochrane Library), and Chinese BioMedical Literature Database (CBM) complemented by manual searches in article references were conducted to identify eligible studies. All cohort studies in which survival and/or prognostic factors for pulmonary metastasectomy from breast cancer were reported were included in the analysis. We calculated the pooled 5-year survival rates, identified the prognostic factors for OS and combined the hazard ratios (HRs) of the identified prognostic factors.
  
  
  RESULTS
  Sixteen studies with a total of 1937 patients were included in this meta-analysis. The pooled 5-year survival rates after pulmonary metastasectomy was 46% [95% confidence interval (95% CI): 43-49%]. The poor prognostic factors were disease-free interval (DFI) (<3 years) with HR =1.70 (95% CI: 1.37-2.10), resection of metastases (incomplete) with HR =2.06 (95% CI: 1.63-2.62), No. of pulmonary metastases (>1) with HR =1.31 (95% CI: 1.13-1.50) and the hormone receptor status of metastases (negative) with HR =2.30 (95% CI: 1.43-3.70).
  
  
  CONCLUSIONS
  Surgery with a relatively high 5-year OS rate after pulmonary metastasectomy (46%), may be a promising treatment for pulmonary metastases in the breast cancer patients with a good performance status and limited disease. The main poor prognostic factors were DFI (<3 years), resection of metastases (incomplete), No. of pulmonary metastasis (>1) and hormone receptor status of metastases (negative). And prospective randomized trials will be needed to address these issues in the future.
authors.affiliation: Department of Thoracic Surgery, West China Hospital, Sichuan University, Chengdu 610041, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Fan
authors.affiliation: Department of Thoracic Surgery, West China Hospital, Sichuan University, Chengdu 610041, China.
authors.forename: Dali
authors.initials: D
authors.lastname: Chen
authors.affiliation: Department of Thoracic Surgery, West China Hospital, Sichuan University, Chengdu 610041, China.
authors.forename: Heng
authors.initials: H
authors.lastname: Du
authors.affiliation: Department of Thoracic Surgery, West China Hospital, Sichuan University, Chengdu 610041, China.
authors.forename: Cheng
authors.initials: C
authors.lastname: Shen
authors.affiliation: Department of Thoracic Surgery, West China Hospital, Sichuan University, Chengdu 610041, China.
authors.forename: Guowei
authors.initials: G
authors.lastname: Che
keywords: Breast cancer; meta-analysis; prognostic factors; pulmonary metastases; systematic review