title: Risk factors for radiation failure in early-stage glottic carcinoma: A systematic review and meta-analysis.
abstract: Radiotherapy is one of the main treatment modalities for early-stage glottic carcinoma. Unfortunately, local failure may occur in a group of cases with T1-T2 glottic carcinoma. This meta-analysis sought to determine risk factors for radiation failure in patients with early-stage glottic carcinoma.
  
  
  
  A systematic and comprehensive search was performed for related studies published between 1995 and 2014. The primary end-point was 5-year local control. Data extraction and analysis were performed using the software STATA/SE 13.1 for Windows.
  
  
  
  Twenty-seven studies were eligible. A higher risk of radiation failure was demonstrated in male patients [relative risk (RR): 0.927, p<0.001] and those with low hemoglobin level (RR: 0.891, p<0.001) with a high agreement between studies (I-squared=0.0%). Moreover, T2 tumors (RR: 0.795, p<0.001), tumors with anterior commissure involvement (RR: 0.904, p<0.001), tobacco use during/after therapy (RR: 0.824, p<0.001), and "bulky" tumors (RR: 1.270, p<0.001] or tumors bigger in size (RR: 1.332, p<0.001]. Poorly differentiated tumors had a questionable risk of local failure, although a moderate to high interstudy heterogeneity was determined. A statistically significant contribution was not detected for age, presence of comorbidity, alcohol use or subglottic extension.
  
  
  
  This is the first meta-analysis which assessed the potential risk factors for radiation failure in patients with early-stage glottic carcinoma. Gender and pretreatment hemoglobin level are major influential factors associated with radiation failure in patients with early-stage glottic carcinoma. However, prospective, randomized clinical trials may permit better stratification of their relative contributions, and those who may benefit more from upfront surgery.
authors.affiliation: Celal Bayar University, Department of Otolaryngology-Head and Neck Surgery, Manisa, Turkey. Electronic address: gorkemeskiizmir@yahoo.com.
authors.forename: Görkem
authors.initials: G
authors.lastname: Eskiizmir
authors.affiliation: Dokuz Eylül University, Institute of Oncology, Izmir, Turkey.
authors.forename: Yasemin
authors.initials: Y
authors.lastname: Baskın
authors.affiliation: Katip Celebi University, Department of Engineering Sciences, Izmir, Turkey.
authors.forename: Femin
authors.initials: F
authors.lastname: Yalçın
authors.affiliation: Dokuz Eylül University, Institute of Oncology, Izmir, Turkey.
authors.forename: Hülya
authors.initials: H
authors.lastname: Ellidokuz
authors.affiliation: University of Pittsburgh, Division of Head Neck Surgery, Pittsburgh, PA, United States.
authors.forename: Robert L
authors.initials: RL
authors.lastname: Ferris
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D005931:Glottis / Q000473:pathology*; D006801:Humans; D007822:Laryngeal Neoplasms / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D012307:Risk Factors
keywords: Glottis; Head and neck neoplasms; Laryngeal neoplasms; Local; Meta-analysis; Neoplasm recurrence; Prognosis; Radiotherapy; Treatment failure