title: Perineural invasion as a prognostic factor for cervical cancer: a systematic review and meta-analysis.
abstract: BACKGROUND
  Recent observational studies have reported that perineural invasion (PNI) may be a negative prognostic factor in cervical cancer.
  
  
  OBJECTIVE
  The purpose of this meta-analysis is to systematically analyse the effect of PNI on overall survival and disease-free survival.
  
  
  METHODS
  The PubMed and Cochrane clinical trials databases were searched for articles with publication dates up to September 2013.
  
  
  METHODS
  Retrospective observational studies with survival analysis for perineural invasion after radical hysterectomy plus lymphadenectomy of cervical cancer were selected.
  
  
  METHODS
  Trial characteristics and outcomes and quality measures based on the Newcastle-Ottawa scale (NOS) were independently extracted. The overall survival and disease-free survival of patients with PNI were measured using a hazard ratio (HR) for time to event outcomes.
  
  
  RESULTS
  The meta-analysis of these studies demonstrated that cervical cancer with PNI was associated with a lower overall survival rate (HR 2.21, 95 % CI 1.36-3.59, P = 0.001). Although the disease-free survival was lower in the PNI group (HR 1.35, 95 % CI 0.78-2.31, P = 0.28), the results were not statistically significant.
  
  
  CONCLUSIONS
  Patients with PNI-positive cervical cancer have a poor overall survival rate; therefore, we can conclude that perineural invasion (PNI) is an adverse prognostic factor in cervical cancer. Based on these results, PNI should be an independent prognostic factor for cervical cancer and the decision to proceed with adjuvant therapy after surgery.
authors: Department of Gynecological Oncology, Second People's Hospital of Sichuan, Sichuan Cancer Hospital, Chengdu, 610041, Sichuan, People's Republic of China.
authors: Ling
authors: L
authors: Cui
authors: Yu
authors: Y
authors: Shi
authors: Guo Nan
authors: GN
authors: Zhang
mesh_terms: D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007044:Hysterectomy; D008197:Lymph Node Excision; D009361:Neoplasm Invasiveness / Q000473:pathology*; D010525:Peripheral Nerves / Q000473:pathology*; D011379:Prognosis; D016019:Survival Analysis; D015996:Survival Rate; D002583:Uterine Cervical Neoplasms / Q000473:pathology* / Q000601:surgery