title: Consolidation radiotherapy in primary central nervous system lymphomas: impact on outcome of different fields and doses in patients in complete remission after upfront chemotherapy.
abstract: OBJECTIVE
  Avoidance radiotherapy or reduction of irradiation doses in patients with primary central nervous system lymphoma (PCNSL) in complete remission (CR) after high-dose methotrexate (HD-MTX)-based chemotherapy has been proposed to minimize the neurotoxicity risk. Nevertheless, no study has focused on the survival impact of radiation parameters, as far as we know, and the optimal radiation schedule remains to be defined.
  
  
  METHODS
  The impact on outcome and neurologic performance of different radiation fields and doses was assessed in 33 patients with PCNSL who achieved CR after MTX-containing chemotherapy and were referred to consolidation whole-brain irradiation (WBRT). Patterns of relapse were analyzed on computed tomography-guided treatment planning, and neurologic impairment was assessed by the Mini Mental Status Examination.
  
  
  RESULTS
  At a median follow-up of 50 months, 21 patients are relapse-free (5-year failure-free survival [FFS], 51%). WBRT doses ≥ 40 Gy were not associated with improved disease control in comparison with a WBRT dose of 30 to 36 Gy (relapse rate, 46% vs. 30%; 5-year FFS, 51% vs. 50%; p = 0.26). Disease control was not significantly different between patients irradiated to the tumor bed with 45 to 54 Gy or with 36 to 44 Gy, with a 5-year FFS of 35% and 44% (p = 0.43), respectively. Twenty patients are alive (5-year overall survival, 54%); WB and tumor bed doses did not have an impact on survival. Impairment as assessed by the Mini Mental Status Examination was significantly more common in patients treated with a WBRT dose ≥ 40 Gy.
  
  
  CONCLUSIONS
  Consolidation with WBRT 36 Gy is advisable in patients with PCNSL in CR after HD-MTX-based chemotherapy. Higher doses do not change the outcome and could increase the risk of neurotoxicity.
authors.affiliation: Unit of Lymphoid Malignancies, Department of Oncology, San Raffaele Scientific Institute, Milan, Italy. andres.ferreri@hsr.it
authors.forename: Andrés José María
authors.initials: AJ
authors.lastname: Ferreri
authors.forename: Chiara
authors.initials: C
authors.lastname: Verona
authors.forename: Letterio Salvatore
authors.initials: LS
authors.lastname: Politi
authors.forename: Anna
authors.initials: A
authors.lastname: Chiara
authors.forename: Lucia
authors.initials: L
authors.lastname: Perna
authors.forename: Eugenio
authors.initials: E
authors.lastname: Villa
authors.forename: Michele
authors.initials: M
authors.lastname: Reni
mesh_terms: D000328:Adult; D000368:Aged; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D001932:Brain Neoplasms / Q000188:drug therapy / Q000401:mortality / Q000532:radiotherapy*; D016543:Central Nervous System Neoplasms / Q000188:drug therapy / Q000401:mortality / Q000532:radiotherapy; D003131:Combined Modality Therapy / Q000379:methods; D016371:Cranial Irradiation / Q000009:adverse effects / Q000379:methods; D018572:Disease-Free Survival; D004334:Drug Administration Schedule; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008223:Lymphoma / Q000188:drug therapy / Q000401:mortality / Q000532:radiotherapy*; D008297:Male; D008609:Mental Status Schedule; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local; D011344:Procarbazine / Q000008:administration & dosage; D011879:Radiotherapy Dosage; D012074:Remission Induction / Q000379:methods*; D012189:Retrospective Studies; D013997:Time Factors; D014750:Vincristine / Q000008:administration & dosage
chemical_list: D011344:Procarbazine; D014750:Vincristine