title: Hodgkin disease survival in Europe and the U.S.: prognostic significance of morphologic groups.
abstract: BACKGROUND
  The survival of patients with Hodgkin disease (HD) varies markedly across Europe and generally is shorter than the survival of patients in the U.S. To investigate these differences, the authors compared population-based HD survival in relation to morphologic type among populations in Europe and the U.S.
  
  
  METHODS
  The authors analyzed 6726 patients from 37 cancer registries that participated in EUROCARE-3 and 3442 patients from 9 U.S. Surveillance, Epidemiology, and End Results (SEER) registries. Patients were diagnosed during 1990 to 1994 and were followed for at least 5 years. The European registries were grouped into EUROCARE West, EUROCARE UK, and EUROCARE East. Morphologic groups were nodular sclerosis, mixed cellularity, lymphocyte depletion, lymphocyte predominance, and not otherwise specified (NOS). The influence of morphology on geographic differences in 5-year relative survival was explored by using multiple regression analysis.
  
  
  RESULTS
  In the model that was adjusted by age, gender, and years since diagnosis, the relative excess risk (RER) of death was 0.93 (95% confidence interval [95% CI], 0.81-1.05) in EUROCARE West, 1.15 (95% CI, 1.04-1.28) in EUROCARE UK, and 1.39 (95% CI, 1.21-1.60) in EUROCARE East (compared with the SEER data). When morphology was included, EUROCARE UK and SEER no longer differed (RER, 1.06; 95% CI, 0.95-1.18). Morphology distribution varied markedly across Europe and much less in the U.S., with nodular sclerosis less common in Europe (45.9%) than the U.S. (61.7%). The RER data showed that patients who had lymphocyte depletion, NOS, and mixed cellularity had a significantly worse prognoses compared with patients who had nodular sclerosis, whereas patients who had lymphocyte predominance had the best prognosis.
  
  
  CONCLUSIONS
  The current results provide population-based evidence that morphology strongly influences the prognosis of patients with HD. However differences in the morphologic case mix explains only some of the geographic variations observed in survival.
authors.affiliation: Epidemiology Unit, Department of Preventive and Predictive Medicine, Istituto Nazionale per lo Studio e la Cura dei Tumori, Milano, Italy. claudia.allemani@istitutotumori.mi.it
authors.forename: Claudia
authors.initials: C
authors.lastname: Allemani
authors.forename: Milena
authors.initials: M
authors.lastname: Sant
authors.forename: Roberta
authors.initials: R
authors.lastname: De Angelis
authors.forename: Rafael
authors.initials: R
authors.lastname: Marcos-Gragera
authors.forename: Jan Willem
authors.initials: JW
authors.lastname: Coebergh
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005060:Europe; D005260:Female; D006689:Hodgkin Disease / Q000401:mortality* / Q000473:pathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D012042:Registries; D018426:SEER Program; D014481:United States