Spinescope Dec 2014

Abstract

Several of the small clinical trials involving recombinant human bone morphogenetic protein-2 showed a higher than expected cancer incidence compared to the control group after high-dose exposure. Kelly et al. performed a study to determine the risk of cancer after spinal arthrodesis with BMP in a larger database study. The authors retrospectively analyzed the incidence of cancer in over 450,000 Medicare patients undergoing spinal arthrodesis between 2005 and 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. The relative risk of developing cancer after BMP exposure was 0.938, 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 and 0.93 in females. The control group showed a higher incidence of each type of cancer except pancreatic cancer. Based on these data, the authors conclude that recent clinical use of BMP was not associated with a detectable increase in the risk of cancer within a mean 2.9-year follow-up window. Unfortunately, in this database study, the total dosage of BMP was not available but was likely lower than the dosage in the FDA trial that reported the higher cancer rate. Although the study has all the limitations of a retrospective database-derived investigation, it has a major advantage of surveying a much larger population than any of the individual clinical trials. Kelly MP, Savage JW, Bentzen SM, Hsu WK, Ellison SA, Anderson PA. J Bone Joint Surg. 2014;96:1417–1422.