title: Incidence Trends in the Diagnosis of Giant Cell Tumor of Bone in Sweden Since 1958.
abstract: BACKGROUND
  The Swedish Cancer Registry (founded in 1958) constitutes a unique resource for epidemiological studies of giant cell tumor of bone with potential for use for population-based studies of incidence over time. The aim of this study was to provide what we believe is the first modern population-based assessment of the incidence trends of giant cell tumor, a unique osteoclastogenic lytic stromal tumor with both benign and malignant histological forms, and to compare the findings with data from the same registry on osteosarcoma, a tumor that may display similar histological characteristics.
  
  
  METHODS
  Cases were identified with use of codes for pathological bone tumor (International Classification of Diseases [ICD]-7 196). Specific morphological coding distinguishes benign (PAD 741) from malignant giant cell tumor (PAD 746) and osteosarcoma (PAD 766).
  
  
  RESULTS
  During the period of 1958 to 2011, 4625 bone tumors were reported, including 505 giant cell tumors (383 benign and 122 malignant) and 1152 osteosarcomas. From 1958 to 1982 the ratio of malignant to benign giant cell tumors was 1.3, whereas from 1983 to 2011 the ratio inverted to 0.09, suggesting a change in the reporting or diagnosis of malignant or benign cases. Cases of giant cell tumor diagnosed from 1983 to 2011 displayed an age and sex distribution (median age at diagnosis, 34.0 years; 54% female) that were consistent with those in large published case series but differed from those in 1958 to 1982 (median age at diagnosis, 31.5 years; 48% female). The most current data (1983 to 2011) showed the giant cell tumor incidence in Sweden to be 1.3 per million per year, while the osteosarcoma incidence was 2.3 per million per year.
  
  
  CONCLUSIONS
  Early Swedish Cancer Registry data (1958 to 1982) revealed a higher proportion of malignant giant cell tumors than seen in large sequential case series and a distinct age and sex profile compared with more recent data (1983 to 2011). This likely represents changes in the diagnostic workup and introduction of multidisciplinary review of giant-cell-containing tumors around 1982. Recent data may reflect the impact of expert centralized biopsy and multidisciplinary case review and more comprehensive reporting of benign giant cell tumors.
authors.affiliation: IMS Health (Pygargus), Sveavägen 155, SE-113 46, Stockholm, Sweden.
authors.forename: Julia
authors.initials: J
authors.lastname: Rockberg
authors.affiliation: Amgen Inc., One Amgen Center Drive, MS 38-2-B, Thousand Oaks, CA 91320-1799.
authors.forename: Bruce A
authors.initials: BA
authors.lastname: Bach
authors.affiliation: Amgen Ltd, 1 Uxbridge Business Park, Sanderson Road, Uxbridge UB8 1DH, England.
authors.forename: Justyna
authors.initials: J
authors.lastname: Amelio
authors.affiliation: Amgen Inc., One Amgen Center Drive, MS 24-2-A, Thousand Oaks, CA 93120-1799.
authors.forename: Rohini K
authors.initials: RK
authors.lastname: Hernandez
authors.affiliation: IMS Health (Pygargus), Sveavägen 155, SE-113 46, Stockholm, Sweden.
authors.forename: Patrik
authors.initials: P
authors.lastname: Sobocki
authors.affiliation: Lund University, SE-221 85 Lund, Sweden.
authors.forename: Jacob
authors.initials: J
authors.lastname: Engellau
authors.affiliation: Karolinska Universitetssjukhuset, Solna, A2:07,171 76 Stockholm, Sweden.
authors.forename: Henrik C F
authors.initials: HC
authors.lastname: Bauer
authors.affiliation: Center for Observational Research, Amgen, Inc., 1120 Veterans Boulevard, ASF3, South San Francisco, CA 94080. E-mail address: aliede@amgen.com.
authors.forename: Alexander
authors.initials: A
authors.lastname: Liede
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D001859:Bone Neoplasms / Q000453:epidemiology* / Q000473:pathology; D002648:Child; D002675:Child, Preschool; D005260:Female; D018212:Giant Cell Tumor of Bone / Q000453:epidemiology* / Q000473:pathology; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D012516:Osteosarcoma / Q000453:epidemiology* / Q000473:pathology; D012042:Registries; D012189:Retrospective Studies; D017678:Sex Distribution; D013548:Sweden / Q000453:epidemiology; D013997:Time Factors; D055815:Young Adult