Glowing tumors: Cutting out cancer by lighting it up
Brain tumors will attack 40,000 Americans this year. Removing the malignant and most aggressive forms can be a tough task for surgeons. It's hard to see where the tumor begins and ends, but glowing technology is shedding light on the problem.
"A patient drinks an agent that gets metabolized by the brain cancer cells into a fluorescent compound that stays within the cells," says Costas G. Hadjipanayis, M.D., Ph.D. chief of neurosurgery service at Emory University Hospital Midtown.
The drug Gliolan has been used safely in thousands of patients in Europe. Now, at Emory University, it's in its first U.S. clinical trial for patients with glioblastomas which are dangerous brain tumors that can be difficult to fully remove.
"You can see with the blood, spinal fluid it's very hard to visualize what's a tumor and what's not," says Hadjipanayis.
The drug, taken hours before surgery, makes the tumor cells light up, helping surgeons identify and remove more of the cancer. The glowing tumor technology helped safely remove an aggressive cancer from Boris Zeide's brain. Other doctors said it would be impossible.
"They were afraid he wouldn't be able to speak or walk. He's not just alive, he's talking," says Liz Zeide, Boris' wife.
Using similar technology, the first fluorescence-guided surgery has been performed on an ovarian cancer patient. Doctors say it helped surgeons spot a tumor 30 times smaller than they would have been able to detect with standard techniques.
Phase two clinical trials for fluorescence-guided surgery started in January in conjunction with the Mayo Clinic. Gliolan is not FDA approved at this point, but more trials are expected. While the two methods can help with tumor removal, patients still need to go through chemotherapy or immunotherapy to lower the risk of the cancer coming back.
BACKGROUND: Glioblastoma (GBM) belongs to a family of brain tumors called "astrocytomas." These are tumors which arise from astrocytes, star-shaped cells of the brain which play a role in supporting normal brain tissue. There are four stages of astrocyomas and GBM is the fourth. It is also the most aggressive type of nervous system tumor. (SOURCES: www.abta.org, www.ncbi.nlm.nih.gov/pubmedhealth, www.webmd.com)
SYMPTOMS: General symptoms of GBM are essentially the same as for other brain tumors, they include, headache, weakness, seizures, clumsiness and having difficulty walking. Specific symptoms will depend on the size and location of the GBM. The symptoms of brain cancer are numerous and not specific to brain tumors, meaning they can be caused by many other illnesses as well. The only way to know for sure what is causing the symptoms is to undergo diagnostic testing. (SOURCES: www.cedars-sinai.edu, www.webmd.com)
SURVIVAL: Most people diagnosed with GBM die of this disease in less than a year. Even under the best of circumstances, in which essentially all of the enhancing tumor seen on MRI scan can be surgically removed and the patients are fully treated with radiation and chemotherapy, the mean survival of this disease is only extended from two to three months to one year. Only about one out of every four patients with this type of tumor survives two years. Prospects are better when:
- The patient is younger than 45
- All or most of the tumor can be removed
- The tumor turns out to be an anaplastic astrocytoma, which is one stage less severe than GBM (SOURCES: www.ncbi.nlm.nih.gov/pubmedhealth, www.cedars-sinai.edu)
THINGS YOU DIDN'T KNOW: Although GBM brain tumors can occur at almost any age, they're most common after 50 years of age. GBM is hard to detect, thus a new drug called gliolan is used to light up the cancer cells. Gliolan is absorbed by cells in the body, where it is converted by enzymes into fluorescent chemicals. When illuminated under blue light of a specific wavelength, the PPIX in the tumor glows an intense red, while the normal brain tissue appears blue. This enables the surgeon to see the tumor more clearly during brain surgery and to remove it more accurately, sparing healthy brain tissue. (SOURCES: www.cedars-sinai.edu, www.ema.europa.eu)
LATEST BREAKTHROUGHS: Winship Cancer Institute researchers are testing an experimental therapy for GBM. The study uses brain imaging in an effort to detect whether the therapy is having an effect after one week. The therapy combines vorinostat, an experimental drug, with temozolomide, which is standard treatment for GBM. The goal of using the vorinostat drug is to turn genes that could suppress tumor growth back on while restoring normal metabolic behavior to the cancer cells, thus halting tumor growth (SOURCE: www.news.emory.edu)
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