Those who have parents, siblings or offspring who have suffered from a brain tumor have a greater chance of developing one themselves, a study by the Yale School of Public Health has found.
The results of the study, published in the July 22 issue of the Journal of Neurosurgery, showed a significant link between meningiomas — the most common type of brain tumor in the United States — and patient family history, suggesting that genetics may play a larger role in the development of these tumors than previously thought. The team of researchers, led by principal investigator Elizabeth B. Claus GRD ’88 MED ’94 SPH ’88, found that brain tumor patients were 4.4 times more likely than non-tumor patients to have an immediate family history of the tumors.
The study also found a possible link between female hormones and brain tumors: Female patients were twice as likely to develop meningioma as the male ones.
The five-year study, which began in 2005 in a number of cities across the United States, compared 1,124 patients with meningioma with a similar number of control patients without meningioma. Patients whose grandparents, aunts, uncles or grandchildren developed meningioma were also tested, but results showed that those with these “second-degree” family histories had a higher, but statistically insignificant, rate of tumor development compared to control patients.
Researchers also found that patients with meningioma had been exposed to radiation more often than control patients. This type of radiation, called ionizing radiation, is thought to cause tumors and is administered during radiotherapy as well as dental and diagnostic X-rays.
Michael McDermott, a neurological surgery professor at the University of California, San Francisco, said that most exposure to ionizing radiation comes from therapy for other medical conditions. He added that pediatric oncologists recommend patients get an MRI brain scan even 10 to 20 years after exposure to this radiation because these patients have a 25-fold risk increase of developing meningioma compared to the normal population.
University of California, San Francisco associate epidemiology and biostatistics professor Joseph Wiemels said the team expected to find a link between meningioma and radiation, but were surprised to discover an unexpected link between allergy and meningioma. The study found that people with allergies were less likely to develop meningioma.
“One thing we expected was to find some link between meningioma and ionizing radiation, and we have found that,” Wiemels said. “We didn’t expect to find a link between meningioma and allergy but there is.”
Wiemels said the study found unexpected results on how certain meningioma risk factors affect men and women differently; for instance, smoking seems to be a risk factor for men but not for women. He said the team hopes to delve further into the topic of gender differences and meningioma development.
The results of Claus’ study could lead to the development of a screening test that would determine a person’s likelihood of developing meningioma, McDermott said. He added that risk exposure from other brain scans could also prove an interesting further study since there is currently little data on the topic.
Neil Patel, a clinical fellow in neuroradiology at Johns Hopkins School of Medicine, said the study affirmed existing beliefs in the field about links between hormonal stimuli, radiation therapy and meningiomas.
“The study suggests potentially important links to new genetic mutations that will undoubtedly be the target of future research,” Patel said.
The Yale research team worked with researchers from M.D. Anderson Cancer Center, Duke University and the University of California, San Francisco.
Meningiomas account for 34 percent of primary brain tumors in the United States, according to the National Brain Tumor Society.