In people under age 30, radiation is a risk factor for a type of brain tumor called a meningioma, a Loyola University Medical Center study has found.
Researchers analyzed records of 35 patients who were diagnosed with meningiomas before age 30. Five had been exposed to ionizing radiation earlier in their lives. They include two patients who received radiation for leukemia at ages 5 and 6; one who received radiation at age 3 for a brain tumor known as a medulloblastoma; and one who received radiation for an earlier skull base tumor that appeared to be a meningioma. The fifth patient had been exposed at age 9 to radiation from the Chernobyl nuclear power plant disaster in Ukraine. Twenty years later, he was diagnosed with a meningioma.
In the five patients, the average latency period for the tumors was 23.5 years.
The study was published in the online journal Neuroscience Discovery
"The results of this preliminary study have prompted us to look closely at radiation's effects on the brain," said Loyola neurosurgeon Vikram Prabhu, MD, first author of the study. Dr. Prabhu specializes in treating brain tumors.
A meningioma is a tumor, usually benign, that arises from the meninges — the membranes that surround the brain and spinal cord. Meningiomas comprise about one-third of all primary brain tumors, but are rare in children and young adults. It is one of the commonest brain tumors treated at Loyola by Dr. Prabhu and his team. They are doing a follow-up study on patients of all ages who have been treated at Loyola for meningiomas. In collaboration with Dr. Omer Iqbal, from the Department of Pathology, they are analyzing the genetics and biology of tumor samples to find how they differ from samples of tumors not linked to radiation.
Loyola oncologist Kevin Barton, MD, a co-author of the study, said: "It is important to compare and contrast these post-radiation meningiomas with de novo meningiomas, both clinically and biologically, in order to further define optimal therapy."
Researchers so far have identified 14 meningioma patients who were exposed to radiation earlier in their lives. They include three patients who were exposed to Chernobyl radiation and 11 patients who received therapeutic radiation for such conditions as leukemia, medulloblastoma tumors and fungal infections of the scalp.
Dr. Edward Melian, a radiation oncologist at Loyola and co-author of the study, said patients generally have done very well with radiation treatments. "Although we have identified radiation as a risk factor for meningiomas, radiation remains an important part of the treatment regimen for certain lesions, and is helping us obtain good results for our patients."
Dr. Prabhu said physicians have become more judicious in using radiation for therapeutic purposes. For example, radiation no longer is used to treat fungal scalp infections.
"We have become more aware of the tumor-inducing properties of radiation," Dr. Prabhu said.
People who have been exposed to large doses of radiation to the head face a small risk of later developing brain tumors. If such a person experiences symptoms associated with brain tumors, including headaches, seizures, vomiting and blurry vision, he or she should see a doctor, Dr. Prabhu said.