title: Radiotherapy of indolent orbital lymphomas : Two radiation concepts.
abstract: OBJECTIVE
  The aim of this work was to retrospectively analyze efficacy, toxicity, and relapse rates of conventional (CRT) and low-dose radiotherapy (LDRT) in patients with indolent orbital lymphomas.
  
  
  METHODS
  From 1987-2014, 45 patients (median age 64 years) with 52 lesions of indolent orbital lymphomas were treated with CRT (median dose 36 Gy, range 26-46 Gy) and 7 patients (median age 75 years) with 8 lesions were treated with LDRT (2 fractions of  2.0 Gy).
  
  
  RESULTS
  Median follow-up was 133 months (range 2-329 months) in the CRT group and 25 months (range 10-41 months) in the LDRT group. Overall response rates were 97.7 % (CRT) and 100 % (LDRT). The 2‑ and 5‑year local progression-free survival (PFS) rates were 93.5 and 88.6 %, distant PFS 95.0 and 89.9 %, and overall survival 100 and 85.6 % after CRT. In the LDRT group, 2‑year local PFS and overall survival remained 100 %, respectively, and distant PFS 68.6 %. Acute radiotherapy-related complications (grades 1-2) were detected in virtually all eyes treated with CRT. Cataracts developed in only patients who were irradiated with more than 34 Gy. LDRT was well tolerated with only mild acute and late complications.
  
  
  CONCLUSIONS
  Primary radiotherapy of indolent orbital lymphomas is an effective treatment with high response rates and excellent local control in CRT and LDRT. In combination with close follow-up, LDRT may be an attractive alternative since re-irradiation even with conventional doses is still feasible.
authors.affiliation: Abteilung RadioOnkologie und Strahlentherapie, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 400, 69120, Heidelberg, Deutschland. Laila.Koenig@med.uni-heidelberg.de.
authors.forename: Laila
authors.initials: L
authors.lastname: König
authors.affiliation: Abteilung RadioOnkologie und Strahlentherapie, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 400, 69120, Heidelberg, Deutschland.
authors.forename: Robert
authors.initials: R
authors.lastname: Stade
authors.affiliation: Abteilung RadioOnkologie und Strahlentherapie, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 400, 69120, Heidelberg, Deutschland.
authors.forename: Juliane
authors.initials: J
authors.lastname: Rieber
authors.affiliation: Abteilung RadioOnkologie und Strahlentherapie, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 400, 69120, Heidelberg, Deutschland.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Debus
authors.affiliation: Abteilung RadioOnkologie und Strahlentherapie, Universitätsklinikum Heidelberg, Im Neuenheimer Feld 400, 69120, Heidelberg, Deutschland.
authors.forename: Klaus
authors.initials: K
authors.lastname: Herfarth
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018572:Disease-Free Survival; D004307:Dose-Response Relationship, Radiation; D005260:Female; D005858:Germany / Q000453:epidemiology; D006801:Humans; D008223:Lymphoma / Q000401:mortality* / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000401:mortality* / Q000517:prevention & control*; D009918:Orbital Neoplasms / Q000401:mortality* / Q000532:radiotherapy*; D015995:Prevalence; D011379:Prognosis; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal / Q000401:mortality* / Q000706:statistics & numerical data; D012189:Retrospective Studies; D012307:Risk Factors; D015996:Survival Rate
keywords: Indolent non-Hodgkin lymphoma; Local progression-free survival; Low-dose radiotherapy; Orbital lymphoma; Treatment outcome