Cancer Risk After Use of Recombinant Bone Morphogenic Protein-2 for Spinal Arthrodesis
Carragee and colleagues recently published an analysis of publicly available raw data from the Medtronic sponsored AMPLIFY study (a randomized controlled trial of patients with degenerative lumbar disease who underwent a single-level instrumented posterolateral arthrodesis with either high-dose BMP or autogenous bone graft). At two years, with 85% follow-up, there were 15 new cancer events in 11 patients compared to 2 new cancer events in the control group. The incidence rate ratio between the two groups was 6.75 (p=0.0026). At 5 years, there was a 37% loss of follow-up, but a significantly greater incidence of cancer events was still observed in the BMP group. The study provides Level II evidence that high dose (40 mg) rhBMP-2 in lumbar spinal arthrodesis was associated with an increased risk of new cancer. Since the commonly used doses vary from 1 to 12 mg of BMP, one cannot make direct conclusions for the lower doses, although the results of the study seems to suggest that there may be an increased risk of carcinogenesis even in the setting of lower doses.