title: Impact of initial tumor volume on radiotherapy outcome in patients with T2 glottic cancer.
abstract: BACKGROUND
  The aim of this study was to quantify the impact of initial tumor volume (TV) on radiotherapy (RT) outcome in patients with T2 glottic cancer.
  
  
  METHODS
  Initial TV was calculated for 115 consecutive patients with T2 glottic cancer who had been treated with definitive RT alone at a single institution.
  
  
  RESULTS
  The results showed strong correlations of TV with 3-year local tumor control (LTC) and disease-free survival (DFS). For TV ≤ 0.7 cm(3), 3-year LTC was 83%; for TV 0.7-3.6 cm(3) this was 70% and for TV 3.6-17 cm(3) 44%. Analysis of total dose vs. initial TV showed that larger T2 glottic tumors with a TV of around 5 cm(3) (2-2.5 cm in diameter with 10(10) cancer cells) need an extra 6.5 Gy to achieve similar 3-year LTC rates as for small tumors with a TV of 0.5 cm(3) (~1 cm in diameter with 10(9) cancer cells).
  
  
  CONCLUSIONS
  Although classification of tumors according to TV cannot replace TNM staging in daily practice, it could represent a valuable numerical supplement for planning the optimal dose fractionation scheme for individual patients.
authors.affiliation: Department of Radiation Oncology, Maria Sklodowska-Curie Memorial Cancer Center and the Institute of Oncology, 44-101, ul. Wybrzeże Armii Krajowej 15, Gliwice, Poland, tomr22@tlen.pl.
authors.forename: T
authors.initials: T
authors.lastname: Rutkowski
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018572:Disease-Free Survival; D019583:Dose Fractionation, Radiation; D005260:Female; D005500:Follow-Up Studies; D005931:Glottis / Q000473:pathology; D006801:Humans; D007822:Laryngeal Neoplasms / Q000401:mortality / Q000473:pathology* / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D013223:Statistics as Topic; D014057:Tomography, X-Ray Computed; D016896:Treatment Outcome; D047368:Tumor Burden / Q000528:radiation effects*