title: Low-dose involved-field radiation in the treatment of non-hodgkin lymphoma: predictors of response and treatment failure.
abstract: OBJECTIVE
  To investigate clinical and pathologic factors significant in predicting local response and time to further treatment after low-dose involved-field radiation therapy (LD-IFRT) for non-Hodgkin lymphoma (NHL).
  
  
  METHODS
  Records of NHL patients treated at a single institution between April 2004 and September 2011 were retrospectively reviewed. Low-dose involved-field radiation therapy was given as 4 Gy in 2 fractions over 2 consecutive days. Treatment response and disease control were determined by radiographic studies and/or physical examination. A generalized estimating equation model was used to assess the effect of tumor and patient characteristics on disease response. A Cox proportional hazards regression model was used to assess time to further treatment.
  
  
  RESULTS
  We treated a total of 187 sites in 127 patients with LD-IFRT. Histologies included 66% follicular, 9% chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma, 10% marginal zone, 6% mantle cell lymphoma (MCL), and 8% other. Median follow-up time was 23.4 months (range, 0.03-92.2 months). The complete response, partial response, and overall response rates were 57%, 25%, and 82%, respectively. A CLL histology was associated with a lower response rate (odds ratio 0.2, 95% confidence interval 0.1-0.5, P=.02). Tumor size, site, age at diagnosis, and prior systemic therapy were not associated with response. The median time to first recurrence was 13.6 months. Those with CLL and age ≤ 50 years at diagnosis had a shorter time to further treatment for local failures (hazard ratio [HR] 3.63, P=.01 and HR 5.50, P=.02, respectively). Those with CLL and MCL had a shorter time to further treatment for distant failures (HR 11.1 and 16.3, respectively, P<.0001).
  
  
  CONCLUSIONS
  High local response rates were achieved with LD-IFRT across most histologies. Chronic lymphocytic leukemia and MCL histologies and age ≤ 50 years at diagnosis had a shorter time to further treatment after LD-IFRT.
authors: Harvard Radiation Oncology Program, Boston, Massachusetts, USA. alrusso@partners.org
authors: Andrea L
authors: AL
authors: Russo
authors: Yu-Hui
authors: YH
authors: Chen
authors: Neil E
authors: NE
authors: Martin
authors: Anant
authors: A
authors: Vinjamoori
authors: Sarah K
authors: SK
authors: Luthy
authors: Arnold
authors: A
authors: Freedman
authors: Evan M
authors: EM
authors: Michaelson
authors: Barbara
authors: B
authors: Silver
authors: Peter M
authors: PM
authors: Mauch
authors: Andrea K
authors: AK
authors: Ng
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D015451:Leukemia, Lymphocytic, Chronic, B-Cell / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy; D008224:Lymphoma, Follicular / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy; D020522:Lymphoma, Mantle-Cell / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy; D008228:Lymphoma, Non-Hodgkin / Q000000981:diagnostic imaging / Q000473:pathology / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D010808:Physical Examination; D016016:Proportional Hazards Models; D011859:Radiography; D011878:Radiotherapy / Q000379:methods; D011879:Radiotherapy Dosage; D017211:Treatment Failure; D047368:Tumor Burden