Researchers at Epworth Hospital in Melbourne, Victoria, Australia, contested the theory that recombinant human bone morphogenetic used in spinal fusion surgeries increases patients' risk of cancer.
The study involved 527 patients who had lumbar spinal fusion surgery using rhBMP between 2002 and 2011. Gregory M. Malham, MB, and Graeme A. Brazenor, MB, performed the procedures. The patients, average age of 58 years old, did not have previous histories of invasive cancer. Graham Giles, PhD, and Roger Milne, PhD, of Cancer Council analyzed the risk of cancer based on patient data and the cancer registry.
The surgeons used rhBMP-2, Infuse, or rhBMP-7, OP-1. The average Infuse dose was 10.2mg and average OP-1 dose was 3.3mg. The fusion rate was similar between the two groups — 90 percent for Infuse and 91.9 percent for OP-1.
Spine published the study.
Here are five takeaways:
1. At a follow-up of 4.4 years, 27 of the 527 patients were diagnosed with invasive cancer. This statistic did not differ significantly from the cancer registry's number observed in a population of the same age and sex.
2. One type of cancer did not dominate. There were 20 Infuse patients diagnosed with cancer and 7 Op-1 patients diagnosed with cancer.
3. The researchers also found low rates of other rhBMP-related issues, like ectopic bone growth. "Off-label use of rhBMP provided high fusion rates with no evidence of a significantly increased risk of cancer," concluded the study authors.
4. The researchers note more studies are necessary to understand the safety and effectiveness of using rhBMP products for spinal fusion, however.
5. The study authors conclude they do not completely agree with the North American Spine Society policy that recommends against rhBMP use for some spinal fusion surgeries.
"Our study represents the first retrospective review of patients treated with rhBMP using verified cancer prevalence from a compulsory state cancer registry," said Dr. Malham. "As powerful as our study is, it is still possible that much longer follow-up may ultimately detect a tendency toward one or more cancers."