Giant cell tumour of bone (GCT) is a primary osteolytic neoplasm, histopathologically characterized by osteoclast-like giant cells and clinically characterized by local bone destruction and high recurrence rates. There is a need to identify risk factors for recurrence. In order to reduce the recurrence rate we initiated an international, multicenter, randomised phase II trial with adjuvantzoledronic acid as compared to standard care for high risk GCT patients.

One hundred and sixteen GCT patients, treated at the LUMC from 1971 to 2006, with a minimal follow-up of a year, were retrospectively analysed for the following risk factors for local recurrence: GCT grade III and tumour involvement into soft tissue caused by ingrowth or fracture. Resection was used as treatment in 21 patients (group A), intralesional surgery with cement or adjuvant in 24 (group B) and intralesional surgery with cementation and adjuvant in 71 patients (group C).

GCT recurred in 5% (1/21) in group A. Risk factors were found in 90% of patients without recurrence (18/20). Group B shows a recurrence of 25% (6/24). Risk factors were found in 83% (5/6) of recurring GCTs, compared with 28% in patients without recurrence. In group C, a recurrence rate of 23% (16/71) was found. Risk factors were present in 94% (15/16) of recurrences, compared to 36% (20/55) in patients without recurrence.

Soft tissue involvement and GCT grade 3 and up are risk factors for recurrence in GCT. Recurrence rates are lowest when resection is used. Risk factors may influence the choice of treatment. High risk patients may benefit from resection or systemic treatment with adjuvant therapy.