MedicalResearch.com Interview with:
Lei Xu, MD, PhD
Steele Laboratory of Tumor Biology
Radiation Oncology Department
Massachusetts General Hospital
Medical Research: What is the background for this study?
Dr. Lei Xu: Neurofibromatosis 2 is characterized by benign tumors that develop throughout the nervous system. The most common site of these tumors is the eighth cranial nerve, which carries hearing and balance information from the ears to the brain. Although these vestibular schwannomas grow slowly, they usually lead to a significant or total hearing loss by young adulthood or middle age. The tumors can also press on the brain stem, leading to headaches, difficulty swallowing and other serious neurologic symptoms. While the tumors can be surgically removed or destroyed with radiation treatment, both approaches can also damage hearing.
Several previous investigations had suggested that – unlike other benign tumors – vestibular schwannomas induce the formation of new blood vessels, as malignant tumors do. A 2009 New England Journal of Medicine study led by Scott Plotkin, MD, PhD, at Massachusetts General Hospital reported that treatment with the antiangiogenesis drug bevacizumab caused shrinkage of NF2-schwannomas in most of the treated patients and improved hearing in more than half. But the limitations of that approach – the fact that not all patients responded, that the hearing improvement was often transient and that some patients could not tolerate long-term bevacizumab treatment – indicated the need to better understand the mechanisms of anti-angiogenesis on the function of tumor-bearing nerves.