title: Extranodal natural killer/T-cell lymphoma, nasal type: the significance of radiotherapeutic parameters.
abstract: BACKGROUND
  The objective of this study was to investigate the correlation between local recurrence and radiotherapeutic parameters, including dose and RT radiotherapy (RT) field.
  
  
  METHODS
  The current study included 35 patients who were diagnosed with immunohistochemically confirmed nasal natural killer (NK)/T-cell lymphoma between 1976 and 2004. There were 21 males and 14 females, and they ranged in age from 18 years to 76 years (median, 51 yrs). The primary tumor originated in the nasal cavity in 28 patients, and 32 patients had Stage I disease. Seventeen patients received treatment solely with RT, and the remaining 18 patients received a combination of chemotherapy and RT. The median tumor dose was 50 grays (Gy) (range, 22-60 Gy). Twenty-seven patients received RT to include all macroscopic lesions, all paranasal sinuses, the palate, and the nasopharynx. Eight patients received RT to all macroscopic lesions with generous margins.
  
  
  RESULTS
  A complete remission (CR) or a CR/unconfirmed was achieved in 28 patients (80%). The 5-year overall survival (OAS) rate, disease-free survival (DFS) rate, and local control probability (LCP) were 47.3%, 42.9%, and 65.2%, respectively. Patients who received RT only to macroscopic lesions fared less well in terms of LCP (LCP 5 years, 71.9% vs. 41.7%; P=0.007). The difference in RT field also affected both the OAS rate and the DFS rate. Patients who received RT doses>or=50 Gy tended to achieve favorable local control.
  
  
  CONCLUSIONS
  In the management of nasal NK/T-cell lymphoma, the RT field affected treatment outcomes. RT doses>or=50 Gy resulted in favorable local control.
authors.affiliation: Department of Radiology, Chiba University Hospital, Chiba, Japan. isobeko@ho.chiba-u.ac.jp
authors.forename: Koichi
authors.initials: K
authors.lastname: Isobe
authors.forename: Takashi
authors.initials: T
authors.lastname: Uno
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Tamaru
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kawakami
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Ueno
authors.forename: Hisashi
authors.initials: H
authors.lastname: Wakita
authors.forename: Jun-ichi
authors.initials: J
authors.lastname: Okada
authors.forename: Jun
authors.initials: J
authors.lastname: Itami
authors.forename: Hisao
authors.initials: H
authors.lastname: Ito
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D018572:Disease-Free Survival; D004307:Dose-Response Relationship, Radiation; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007694:Killer Cells, Natural; D016399:Lymphoma, T-Cell / Q000473:pathology / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D009669:Nose Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D012189:Retrospective Studies; D016896:Treatment Outcome