title: Additional survival benefit of involved-lesion radiation therapy after R-CHOP chemotherapy in limited stage diffuse large B-cell lymphoma.
abstract: OBJECTIVE
  The purpose of this study was to evaluate the role of involved-lesion radiation therapy (ILRT) after rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) chemotherapy in limited stage diffuse large B-cell lymphoma (DLBCL) by comparing outcomes of R-CHOP therapy alone with R-CHOP followed by ILRT.
  
  
  METHODS
  We identified 198 patients treated with R-CHOP (median, 6 cycles) for pathologically confirmed DLBCL of limited stage from July 2004 to December 2012. Clinical characteristics of these patients were 33% with stage I and 66.7% with stage II; 79.8% were in the low or low-intermediate risk group; 13.6% had B symptoms; 29.8% had bulky tumors (≥ 7 cm); and 75.3% underwent ≥ 6 cycles of R-CHOP therapy. RT was given to 43 patients (21.7%) using ILRT technique, which included the prechemotherapy tumor volume with a median margin of 2 cm (median RT dose: 36 Gy).
  
  
  RESULTS
  After a median follow-up of 40 months, 3-year progression-free survival (PFS) and overall survival (OS) were 85.8% and 88.9%, respectively. Multivariate analysis showed ≥ 6 cycles of R-CHOP (PFS, P=.004; OS, P=.004) and ILRT (PFS, P=.021; OS, P=.014) were favorable prognosticators of PFS and OS. A bulky tumor (P=.027) and response to R-CHOP (P=.012) were also found to be independent factors of OS. In subgroup analysis, the effect of ILRT was prominent in patients with a bulky tumor (PFS, P=.014; OS, P=.030) or an elevated level of serum lactate dehydrogenase (LDH; PFS, P=.004; OS, P=.012).
  
  
  CONCLUSIONS
  Our results suggest that ILRT after R-CHOP therapy improves PFS and OS in patients with limited stage DLBCL, especially in those with bulky disease or an elevated serum LDH level.
authors.affiliation: Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Jeanny
authors.initials: J
authors.lastname: Kwon
authors.affiliation: Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Korea; Cancer Research Institute, Seoul National University College of Medicine, Seoul, Korea; Institute of Radiation Medicine, Medical Research Center, Seoul National University, Seoul, Korea. Electronic address: ihkim@snu.ac.kr.
authors.forename: Il Han
authors.initials: IH
authors.lastname: Kim
authors.affiliation: Department of Radiation Oncology, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Byoung Hyuck
authors.initials: BH
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: Tae Min
authors.initials: TM
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea.
authors.forename: Dae Seog
authors.initials: DS
authors.lastname: Heo
mesh_terms: D000293:Adolescent; D000328:Adult; D000369:Aged, 80 and over; D000704:Analysis of Variance; D058846:Antibodies, Monoclonal, Murine-Derived / Q000008:administration & dosage; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000008:administration & dosage / Q000627:therapeutic use*; D014408:Biomarkers, Tumor / Q000097:blood; D003131:Combined Modality Therapy / Q000379:methods; D003520:Cyclophosphamide / Q000008:administration & dosage; D018572:Disease-Free Survival; D004317:Doxorubicin / Q000008:administration & dosage; D005260:Female; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000097:blood; D016403:Lymphoma, Large B-Cell, Diffuse / Q000188:drug therapy* / Q000201:enzymology / Q000401:mortality* / Q000473:pathology / Q000532:radiotherapy*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011241:Prednisone / Q000008:administration & dosage; D000069283:Rituximab; D016896:Treatment Outcome; D047368:Tumor Burden; D014750:Vincristine / Q000008:administration & dosage; D055815:Young Adult
chemical_list: D058846:Antibodies, Monoclonal, Murine-Derived; D014408:Biomarkers, Tumor; C571759:R-CHOP protocol; D000069283:Rituximab; D014750:Vincristine; D004317:Doxorubicin; D003520:Cyclophosphamide; D007770:L-Lactate Dehydrogenase; D011241:Prednisone