title: Prognostic nomogram for diffuse large B-cell lymphoma incorporating the International Prognostic Index with interim-positron emission tomography findings.
abstract: OBJECTIVE
  Results from interim-positron emission tomography (PET) studies in diffuse large B-cell lymphoma (DLBCL) patients are varied. We evaluated the prognostic value of interim-PET in our centre. To improve concordance, interim-PET was combined with the International Prognostic Index (IPI).
  
  
  METHODS
  We retrospectively reviewed 100 new consecutive DLBCL patients treated with immunochemotherapy from 2005 to 2010. Twenty-four patients did not receive interim-PET and were excluded. Interim-PET images were re-examined using a qualitative assessment technique. Progression-free survival (PFS) and overall survival (OS) were analysed by the Cox proportional hazards model and prognostic accuracy was assessed using Harrell's C statistics (C).
  
  
  RESULTS
  Eleven patients were positive, and 65 were negative at interim-PET. The 2-year OS and PFS were 70.8% and 60.0%, respectively, in the PET-negative group, 36.4% and 36.4% for the PET-positive group (log-rank P-value 0.0008 for PFS, 0.0001 for OS). The IPI and interim-PET were minimally correlated. On Cox regression analysis, both were significant indicators of PFS (P < 0.001 and P = 0.002 respectively). The prognostic accuracy for PFS of a negative PET result was limited (C = 0.63), as it was for IPI (C = 0.75), but with the two indicators combined, the predictive accuracy was improved (C = 0.81). A nomogram, predictive for relapse-free survival at 2 years, was constructed.
  
  
  CONCLUSIONS
  In DLBCL patients treated with immunochemotherapy, the IPI and interim-PET provide independent prognostic information. In combination, a more powerful predictive model may be created as a nomogram. This can be refined in prospective trials and may help clinical decision making.
authors.affiliation: Haematology Department, Sir Charles Gairdner Hospital, Perth, Western Australia, Australia.
authors.forename: A
authors.initials: A
authors.lastname: Chow
authors.forename: M
authors.initials: M
authors.lastname: Phillips
authors.forename: T
authors.initials: T
authors.lastname: Siew
authors.forename: G
authors.initials: G
authors.lastname: Cull
authors.forename: B
authors.initials: B
authors.lastname: Augustson
authors.forename: M
authors.initials: M
authors.lastname: Ward
authors.forename: D
authors.initials: D
authors.lastname: Joske
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D038622:Internationality; D016403:Lymphoma, Large B-Cell, Diffuse / Q000000981:diagnostic imaging* / Q000453:epidemiology* / Q000628:therapy; D008297:Male; D008875:Middle Aged; D049451:Nomograms; D049268:Positron-Emission Tomography / Q000379:methods*; D011379:Prognosis; D012189:Retrospective Studies; D016896:Treatment Outcome; D055815:Young Adult
keywords: International Prognostic Index; PET scan; diffuse large B-cell lymphoma; lymphoma; nomogram; prognosis