title: Limited-stage diffuse large B-cell lymphoma treated with abbreviated systemic therapy and consolidation radiotherapy: involved-field versus involved-node radiotherapy.
abstract: BACKGROUND
  For limited-stage diffuse large B-cell lymphoma (DLBCL), treatment decisions are often influenced by toxicity profiles. One strategy that minimizes chemotherapy-induced toxicities is abbreviated chemotherapy plus consolidation involved-field radiotherapy (IFRT). Involved-node radiotherapy (INRT) is a new concept to DLBCL, aimed to reduce radiotherapy-induced toxicities. We retrospectively review the long-term outcomes of limited-stage DLBCL treated with abbreviated systemic therapy and radiotherapy focusing on field size: IFRT versus INRT.
  
  
  METHODS
  The British Columbia Cancer Agency Lymphoid Cancer Database was used to identify patients diagnosed with limited-stage DLBCL (stage I/II, without B-symptoms; bulk < 10 cm) from 1981 to 2007. Patients were prescribed 3 cycles of chemotherapy plus IFRT (1981-1996) or INRT≤5 cm (1996-2007), defined as INRT to the prechemotherapy involved nodes with margins ≤ 5 cm.
  
  
  RESULTS
  A total of 288 patients were identified: 56% were aged >60 years, 34% had stage II disease, 55% had extranodal disease, 19% had elevated lactate dehydrogenase levels, and 15% received rituximab. The two radiotherapy groups were IFRT (138 patients; 48%) and INRT≤5cm (150 patients; 52%); median follow-up was 117 and 89 months, respectively. Distant relapse was the most common site of failure in both groups. After INRT≤5 cm, marginal recurrence was infrequent (2%). Time to progression (P = .823), progression-free survival (P = .575), and overall survival (P = .417) were not significantly different between the radiotherapy cohorts. Radiotherapy field size was not a significant prognostic factor on multivariate analyses.
  
  
  CONCLUSIONS
  This research is the first known body of work to apply the concept of INRT to limited-stage DLBCL. Reducing the field size from IFRT to INRT≤5 cm maintains a low marginal recurrence risk with no impact on overall outcome.
authors.affiliation: Department of Radiation Oncology and Cancer Imaging, Peter MacCallum Cancer Centre, Melbourne, Australia. Belinda.Campbell@petermac.org
authors.forename: Belinda A
authors.initials: BA
authors.lastname: Campbell
authors.forename: Joseph M
authors.initials: JM
authors.lastname: Connors
authors.forename: Randy D
authors.initials: RD
authors.lastname: Gascoyne
authors.forename: W James
authors.initials: WJ
authors.lastname: Morris
authors.forename: Tom
authors.initials: T
authors.lastname: Pickles
authors.forename: Laurie H
authors.initials: LH
authors.lastname: Sehn
mesh_terms: D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D003131:Combined Modality Therapy / Q000009:adverse effects; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D015182:Lymphatic Irradiation; D016403:Lymphoma, Large B-Cell, Diffuse / Q000188:drug therapy* / Q000401:mortality / Q000473:pathology / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies