title: Rates and durability of response to salvage radiation therapy among patients with refractory or relapsed aggressive non-Hodgkin lymphoma.
abstract: OBJECTIVE
  To evaluate the response rate (RR) and time to local recurrence (TTLR) among patients who received salvage radiation therapy for relapsed or refractory aggressive non-Hodgkin lymphoma (NHL) and investigate whether RR and TTLR differed according to disease characteristics.
  
  
  METHODS
  A retrospective review was performed for all patients who completed a course of salvage radiation therapy between January 2001 and May 2011 at Brigham and Women's Hospital/Dana-Farber Cancer Institute. Separate analyses were conducted for patients treated with palliative and curative intent. Predictors of RR for each subgroup were assessed using a generalized estimating equation model. For patients treated with curative intent, local control (LC) and progression-free survival were estimated with the Kaplan-Meier method; predictors for TTLR were evaluated using a Cox proportional hazards regression model.
  
  
  RESULTS
  Salvage radiation therapy was used to treat 110 patients to 121 sites (76 curative, 45 palliative). Salvage radiation therapy was given as part of consolidation in 18% of patients treated with curative intent. Median dose was 37.8 Gy, with 58% and 36% of curative and palliative patients, respectively, receiving 39.6 Gy or higher. The RR was high (86% curative, 84% palliative). With a median follow-up of 4.8 years among living patients, 5-year LC and progression-free survival for curative patients were 66% and 34%, respectively. Refractory disease (hazard ratio 3.3; P=.024) and lack of response to initial chemotherapy (hazard ratio 4.3; P=.007) but not dose (P=.93) were associated with shorter TTLR. Despite doses of 39.6 Gy or higher, 2-year LC was only 61% for definitive patients with refractory disease or disease that did not respond to initial chemotherapy.
  
  
  CONCLUSIONS
  Relapsed or refractory aggressive NHL is responsive to salvage radiation therapy, and durable LC can be achieved in some cases. However, refractory disease is associated with a shorter TTLR, suggesting that radiation dose escalation, addition of radiosensitizers, or a combination of both may be indicated in these patients.
authors.affiliation: Department of Radiation Oncology, University of Washington, Seattle, Washington. Electronic address: ydt2@uw.edu.
authors.forename: Yolanda D
authors.initials: YD
authors.lastname: Tseng
authors.affiliation: Department of Biostatistics and Computational Biology, Dana-Farber Cancer Institute, Boston, Massachusetts.
authors.forename: Yu-Hui
authors.initials: YH
authors.lastname: Chen
authors.affiliation: Department of Biostatistics and Computational Biology, Dana-Farber Cancer Institute, Boston, Massachusetts; Department of Biostatistics, Harvard School of Public Health, Boston, Massachusetts.
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Catalano
authors.affiliation: Department of Radiation Oncology, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts.
authors.forename: Andrea
authors.initials: A
authors.lastname: Ng
mesh_terms: D058846:Antibodies, Monoclonal, Murine-Derived / Q000008:administration & dosage; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000008:administration & dosage / Q000627:therapeutic use; D003520:Cyclophosphamide / Q000008:administration & dosage; D018572:Disease-Free Survival; D004317:Doxorubicin / Q000008:administration & dosage; D005260:Female; D006801:Humans; D008228:Lymphoma, Non-Hodgkin / Q000188:drug therapy / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000188:drug therapy / Q000401:mortality / Q000532:radiotherapy*; D010166:Palliative Care; D011239:Prednisolone / Q000008:administration & dosage; D011241:Prednisone / Q000008:administration & dosage; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal / Q000379:methods; D012044:Regression Analysis; D012189:Retrospective Studies; D000069283:Rituximab; D016879:Salvage Therapy / Q000009:adverse effects / Q000379:methods*; D013997:Time Factors; D014750:Vincristine / Q000008:administration & dosage
chemical_list: D058846:Antibodies, Monoclonal, Murine-Derived; C571759:R-CHOP protocol; D000069283:Rituximab; D014750:Vincristine; D004317:Doxorubicin; D003520:Cyclophosphamide; D011239:Prednisolone; D011241:Prednisone