Cancer Risk from Bone Morphogenetic Protein Exposure in Spinal Arthrodesis

Background: The U.S. Food and Drug Administration reported a higher incidence of cancer in patients who had spinal arthrodesis and were exposed to a high dose of recombinant human bone morphogenetic protein-2 (rhBMP-2) compared with the control group in a randomized controlled trial. The purpose of this study was to determine the risk of cancer after spinal arthrodesis with BMP. Methods: We retrospectively analyzed the incidence of cancer in 467,916 Medicare patients undergoing spinal arthrodesis from 2005 to 2010. Patients with a preexisting diagnosis of cancer were excluded. The average follow-up duration was 2.85 years for the BMP group and 2.94 years for the control group. The main outcome measure was the relative risk of developing new malignant lesions after spinal arthrodesis with or without exposure to BMP. Results: The relative risk of developing cancer after BMP exposure was 0.938 (95% confidence interval [95% CI]: 0.913 to 0.964), which was significant. In the BMP group, 5.9% of the patients developed an invasive cancer compared with 6.5% of the patients in the control group. The relative risk of developing cancer after BMP exposure was 0.98 in males (95% CI: 0.94 to 1.02) and 0.93 (95% CI: 0.90 to 0.97) in females. The control group showed a higher incidence of each type of cancer except pancreatic cancer. Conclusions: Recent clinical use of BMP was not associated with a detectable increase in the risk of cancer within a mean 2.9-year time window. Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.