Glioblastoma: New Treatments Offer Hope in the Battle Against This Aggressive Brain Tumor
November, 2008 -- Glioblastoma is one of the most common forms of brain tumor. That said, it is still a very rare disease, affecting about five out of every 100,000 people in the U.S. Unfortunately, it is also one of the most malignant forms of brain cancer, with only one out of four people with glioblastoma surviving for two years after diagnosis according to PinnacleCare Center of Excellence Cedars-Sinai.
The most common symptoms of brain tumors include deep, dull headaches that recur often and last for long periods of time, difficulty walking or talking, dizziness, vision problems, vomiting, mental status changes and seizures. The symptoms can vary depending on the size and location of the tumor. Though glioblastomas can affect people of all ages, they are most common after age 50 and affect more men than women.
“The diagnosis of a malignant brain tumor is certainly a life-altering event,” says Dr. Miles J. Varn, PinnacleCare’s Chief Medical Officer. “But research and new genetic discoveries are offering people with glioblastoma more treatment options then have ever been available before and extending survival.”
A new era of treatment and hope
The standard of care for glioblastoma includes surgery to remove as much of the tumor as possible. This surgery is particularly difficult because glioblastoma tends to spread diffusely throughout the brain with bits of tumor that act like invasive tentacles. All of the tumor cannot be removed, but surgery does decrease the amount of tumor that needs to be treated with radiation and chemotherapy.
Surgery is followed by radiation and chemotherapy. In some cases, the surgeon will place dissolvable wafers made of chemotherapy drugs on or near the remaining tumor. This targeted therapy boosts the amount of medication delivered to the tumor and also reduces side effects. Most patients also undergo systemic chemotherapy with temozolmide which a recent study in Switzerland found can extend survival to four years compared to an average survival of six months to a maximum of two years.
“The standard of care for glioblastoma has remained virtually unchanged for decades,” notes Dr. Henry Friedman, Member of PinnacleCare’s Medical Advisory Board and Deputy Director at The Preston Robert Tisch Brain Tumor Center at Duke and professor of Neuro-Oncology. “That standard is mediocre. We need to do more and be more aggressive with this disease. New treatments including monoclonal antibodies and a vaccine in development have the potential to significantly impact the outcome for people with glioblastoma.”
Dr. Friedman and his colleagues at Duke took part in the development of a new targeted investigational treatment approach that uses a monoclonal antibody that binds to proteins in tumor cells and a radioactive isotope that kills those cells. After surgery to resect as much of the tumor as possible, the treatment, known as NeuradiabTM , is injected by catheter into the space where the tumor was removed. It seeks out a protein produced by tumor cells, then delivers the radiation only to those cells. To date, data from the nationwide Phase III trial of the treatment has shown an increase in the length of survival by up to six months.
“Our experience has been provocative for both new and recurring glioblastomas,” says Dr. Friedman.
Vaccines, smart bombs and genetic revelations
Another new treatment under investigation is a vaccine designed to initiate an immune response that attacks the tumor. The vaccine, CDX-110, has been developed to treat a sub-type of glioblastoma with a protein mutation that causes rapid, unchecked cell division which allows the tumor to thrive and grow. With this type of tumor, almost no one survives two years.
CDX-110 was developed by Dr. John Samson, a Duke neurosurgeon and neuro-oncologist, and Dr. Amy Heimberger, a neurosurgeon at PinnacleCare Center of Excellence the M.D. Anderson Cancer Center. So far, trial results are encouraging, with 65 percent of those who received the vaccine still alive two years after treatment compared to the nearly zero percent predicted survival rate for people with this class of tumor. In addition, the vaccine delayed recurrence for 15 months compared to recurrence after six months for patients who receive the standard treatment.
For recurrent glioblastoma, treatment with the anti-cancer drug Avastin has produced intriguing results. The drug prevents the tumor from growing new blood vessels to support it, stopping tumor growth. In a Duke study, Avastin nearly doubled expected survival to six months. “There is no standard treatment that improves survival, so this is extremely promising,” says Dr. James Vredenburgh, a Duke neuro-oncologist and the study’s principal investigator.
There are many other treatments in development and clinical trials. At the M.D. Anderson Cancer Center, researchers are working on what they’ve dubbed a “viral smart bomb,” a strain of adenovirus that prevents cancer cells from reproducing. At that institution and others around the country, researchers are testing another vaccine that targets a mutation of the epidermal growth factor, a protein that they believe helps glioblastomas to spread so quickly and aggressively. The experimental drug cediranib, which inhibits vascular endothelial growth factor receptors, is also in clinical trials for glioblastoma and has shown promise for people with recurrent glioblastoma that has not responded to other treatments. One non-drug approach in very preliminary trials, the Novo-TTF, uses intermediate frequency electrical fields to interrupt cancer cell division.
On the genetic front, the Cancer Genome Atlas research network recently published new findings on the genetic flaws in glioblastoma. One of the most important findings suggests why some glioblastomas are resistant to a chemotherapy agent. By uncovering gene mutations, the scientists have opened the door for the development of treatments specifically targeted to address these flaws.
PinnacleCare: Your partner in the most important battle of your life
If you or a member of your family is battling brain cancer, your PinnacleCare Advocate Team can provide information on treatment options and clinical trials, expedited access to the nation’s top neuro-oncology specialists and the compassionate support and encouragement that are key elements in dealing with a life-threatening condition.
“We have entered a new era of hope in the treatment of glioblastoma,” adds Dr. Varn. “It’s a rapidly evolving field that is changing the way we approach this disease.”
“Genetic mutations linked to deadly cancers.” This article from The Washington Post explores genetic discoveries about glioblastoma that may speed the development of new treatments. http://www.washingtonpost.com/wp-dyn/content/article/2008/09/04/AR200809...