Trends in Giant Cell Tumour of the Bone and Osteosarcoma Incidence in the Sweden (1958-2011)

Abstract

ABSTRACT Aim: Giant Cell Tumour of the Bone (GCTB) is a rare, histologically benign but locally aggressive neoplasm of the bone that also has a less common malignant form. There are limited data on the epidemiology of GCTB as few population-based cancer registries record incidence of benign bone tumours. The Swedish Cancer Registry (SCR) was introduced in 1958 as a national and compulsory registration of all patients diagnosed with a malignancy, including GCTB. The objective of this study was to evaluate reported trends in the incidence of GCTB, compared to osteosarcoma (an osteolytic and osteoblastic malignant tumour with distinctive histology that may contain multinuclear giant cells). Methods: Patients were identified in the SCR with tumour of bone codes (ICD-7 196). Specific and verified morphological coding distinguishes benign GCTB (PAD 741) from malignant GCTB (PAD 746) and osteosarcoma (PAD 766). Results: There were 4625 bone tumours reported to the SCR between 1958-2011, including 505 GCTB (383 benign, 122 malignant) and 1152 osteosarcoma. Osteosarcoma was more common than GCTB (2.3 to 1 ratio) and had a peak incidence in the second decade of life, whereas GCTB peak incidence was between ages 20 and 40. There was a subtle decline in the incidence of osteosarcoma, whereas the distribution of malignant and benign GCTB inverted around 1982 with fewer malignant and more benign cases reported in the SCR. The ratio of malignant to benign GCTB before 1982 was 1.3 (95/73) and 1983 forward was 0.09 (27/310). The incidence rate of benign GCTB in Sweden was 1.1 per million per year in recent data (1992-2011). Conclusions: The reporting of GCTB to the SCR has improved over the last 50 years. GCTB trends in Sweden can be attributed to the formation of the Scandinavian Sarcoma Group (SSG) in 1979. The SSG introduced centralized treatment and review of sarcoma patients thereby reducing misclassification of sarcoma and confirming that malignant GCTB is rare. The SCR remains one of the few national registries that routinely capture GCTB and is a robust source for epidemiology studies in this disease, although validation studies are needed to further confirm benign and malignant classification. Disclosure: A. Liede: Employed by Amgen Inc, including stock ownership; J. Sandberg: Employed by IMS Health, consultant for Amgen Inc.; J. Amelio: Employed by Amgen Ltd, including stock ownership; R.K. Hernandez: Employed by (and stock ownership) Amgen Inc.; P. Sobocki: Employed by IMS Health, consultant for Amgen Inc.; H.C.F. Bauer: Advisory board member (osteosarcoma) with Eli Lilly; B. Bach: Employed by Amgen Inc. including stock ownership; J. Engellau: Member of advisory board for Amgen and Genovis Inc. Also, lectured for Amgen Ltd (on giant cell tumor of bone).