title: Changes in epidemiologic features of testicular germ cell cancer: age at diagnosis and relative frequency of seminoma are constantly and significantly increasing.
abstract: OBJECTIVE
  Testicular germ cell tumors (GCTs) have their incidence peak in the third and fourth decades of life. Histologically, GCTs comprise of seminoma and nonseminoma at almost equal proportions with a slight preponderance of nonseminoma in most of the major series. Since decades, there is a shift toward decreasing age at presentation. Recently, there are suggestions of a reversal of the age trend, and also, the histologic subtype ratio appears to shift toward seminoma. We retrospectively looked to our patient populations to verify these recent trends.
  
  
  METHODS
  A total of 2,482 patients with histologically proven GCT diagnosed between 1976 and 2010 were retrospectively evaluated regarding the year of diagnosis, histology of primary tumor, and age at presentation. Patients were categorized according to the following time periods of treatment: before 1990, 1990 to 1994, 1995 to 1999, 2000 to 2004, and 2005 to 2010. Mean age and relative proportion of seminoma were compared among patient categories by employing the chi-square test and analysis of variance, respectively.
  
  
  RESULTS
  The mean age significantly increased from 28 to 36 years. The age difference between the 2 histologic subtypes remained constant between 6 and 8 years during the entire observation period. The relative proportion of seminoma continuously increased from 30.9% to 56% (P <0.001).
  
  
  CONCLUSIONS
  There is evidence of a significant shift toward older age at diagnosis of GCT. In addition, the proportion of seminoma is constantly increasing at the expense of nonseminoma. The reasons for these developments are obscure. However, 2 old theories regarding the pathogenesis of GCT may receive support from our results: first, the theory of divergent pathogenetic pathways of seminoma and nonseminoma and second, the involvement of postnatal environmental factors in the pathogenesis of GCTs.
authors: Department of Urology, Federal Armed Forces Hospital, Hamburg, Germany; Department of Urology, University Hospital Hamburg Eppendorf, Hamburg, Germany. Electronic address: dr.christianruf@gmx.de.
authors: Christian G
authors: CG
authors: Ruf
authors: Department of Urology, University Hospital Hamburg Eppendorf, Hamburg, Germany.
authors: Hendrik
authors: H
authors: Isbarn
authors: Department of Urology, Federal Armed Forces Hospital, Hamburg, Germany.
authors: Walter
authors: W
authors: Wagner
authors: Department of Urology, University Hospital Hamburg Eppendorf, Hamburg, Germany.
authors: Margit
authors: M
authors: Fisch
authors: Department of Urology, Federal Armed Forces Hospital, Hamburg, Germany.
authors: Cord
authors: C
authors: Matthies
authors: Department of Urology, Albertinen-Hospital, Hamburg, Germany.
authors: Klaus-Peter
authors: KP
authors: Dieckmann
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D017668:Age of Onset; D000368:Aged; D000369:Aged, 80 and over; D006801:Humans; D008297:Male; D008875:Middle Aged; D009373:Neoplasms, Germ Cell and Embryonal / Q000175:diagnosis* / Q000453:epidemiology* / Q000601:surgery; D012189:Retrospective Studies; D018239:Seminoma / Q000175:diagnosis* / Q000453:epidemiology* / Q000601:surgery; D013736:Testicular Neoplasms / Q000175:diagnosis* / Q000453:epidemiology* / Q000601:surgery; D055815:Young Adult
keywords: Age at diagnosis; Epidemiology; Nonseminoma; Seminoma; Testicular germ cell tumor