News Room
Cancer experts talk about Sen. Ted Kennedy's prospects
by Jill Armentrout | The Saginaw News
Thursday May 22, 2008, 7:33 AM
Gene-based therapy may prove the best hope for treating the type of cancerous brain tumor that threatens Sen. Edward M. Kennedy's life, an expert in the field says.
But, while researchers have reported some breakthrough advances in the search for a genetic cure, it likely won't become available in time to help him.
"We've been working on this, but it's a long road," said Dr. E. Malcolm Field, a Saginaw Township neurosurgeon with St. Mary's of Michigan hospital.
"Eventually we will get there, but it's taking too long for me to be happy with it."
Doctors at Massachusetts General performed a biopsy Monday that led them to conclude that the Massachusetts Democrat has a malignant glioma.
Such tumors almost always are fatal, said Field, who has worked with Northwestern University in Evanston, Ill. toward a gene replacement breakthrough that could greatly reduce the aggressiveness of this cancer.
Kennedy, the 76-year-old senator and the last living son in a famed political family, has a malignant glioma in his left parietal lobe -- the part of the brain that governs sensation, movement and language. A seizure in his home Saturday morning led to the diagnosis. Doctors find malignant gliomas in about 9,000 Americans a year.
"These cancers infiltrate from one side of the brain to the other," Field said. "The treatment usually is whole brain radiation, with a boost at the end to the main tumor.
"Then if it grows again, they could use radiosurgery such as CyberKnife to treat a localized tumor and salvage his life for a while."
St. Mary's recently purchased the CyberKnife technology to treat inoperable cancers and other tumors in the brain and other organs. Radiosurgery uses precise blasts of radiation to destroy tumors.
MidMichigan Medical Center in Midland has used its Gamma Knife radiosurgery system to treat 28 patients with glioblastoma, the most serious type of glioma. Gliomas are primary brain tumors that originate from glial cells -- cells that surround and support nerve cells.
"The role for Gamma Knife is secondary, after possible surgery, then radiation and chemotherapy," said Dr. Brian Copeland, chief neurosurgeon at MidMichigan and medical director of Gamma Knife. "If the patient responds and the cancer reoccurs, there is a role for Gamma Knife."
That type of radiosurgery works only on tumors smaller than 3.5-centimeters in diameter, Copeland said.
"It's very rare that this cancer is cured. We can control it and have had several patients survive several years."
More than 100 chemotherapy and radiation treatments fight this cancer, but most show little promise, Field said. Tumor cells can repair their DNA. Gene therapy finds places in the DNA where genes are deleted as the cells mutate.
Nearly seven years ago, scientists at the Falk Center for Molecular Therapeutics at Northwestern University made a breakthrough that could greatly reduce the aggressiveness of this cancer by replacing the missing sialyltransferase gene. Tests showed that injecting the enzyme along with cancer cells into laboratory mice stopped the tumor growth, said Falk Director Joseph R. Moskal.
With researchers at the Field Neurosciences Institute, 4677 Towne Centre in Saginaw Township, the Northwestern team is completing studies the government requires to bring the therapy to human trials -- which could happen in Saginaw within two years, Field said.
As a principal investigator of the study and founder of the institute, Field has contributed dozens of brain tumor samples to the Falk Center -- all representing patients he couldn't save.
"There are some other trials for gene therapy going on that use a growth factor inhibitor, but they haven't been proven," he said.
"Kennedy's situation is sad. He doesn't have much time, based on speculation of the case. His symptoms will likely grow much worse, but he could be able to function for a while. Doctors need to do everything they can to preserve his quality of life for as long as possible."
Doctors announced Kennedy has recovered quickly from the brain biopsy. They said he will recuperate at his home over the Memorial Day weekend while awaiting further test results that will help determine his treatment plan.
During the annual James E. O'Neill Jr. memorial lecture at Saginaw Valley State University in 2006, Field said that in his 44 years of work he'd only seen four people with glioblastoma enjoy long-term survival.
The tumors can spread all over the brain, making them difficult to treat. Even when a surgeon removes the mass, the cells continue to spread out and form mutations.
Kennedy's disease could give more impetus to continued research, Field said.
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