Discovery to Recovery. In this blog, she discusses treatments for brain cancer.
Neurosurgery: The Crux of Treatment for Brain Cancer
"The neurosurgeon's goal is take out as much of the tumor as possible safely, " says Steven Brem, MD, conference chair, and director of neurosurgical oncology.
"Personalized medicine has become something of a buzz work in medicine, but it is true for brain cancer patients,” says Donald O'Rourke, MD, associate professor of neurosurgery.
Penn neurosurgeons are using improved imaging techniques for "neuronavigation." This approach provides real-time, 3D views for the surgeon as he operates - allowing for maximum safe resection of the tumor and avoiding normal tissue. This is particularly crucial in preserving language function and motor skills.
Radiation Therapy: The Full Spectrum of Options
"Penn has the largest, most advanced proton facility in the world, one of only 10 in the United States. We also have the unique advantage of having all of our radiation facilities integrated under one roof, "
Robert Lustig, MD, professor of radiation oncology.
Radiation therapy plays a key role in the treatment of most brain cancers. Penn offers the full range of treatment modalities including one of only 10 proton facilities in the country. Patients often are unsure of the relative benefits or indications for different kinds of radiation therapy, for example, protons vs. the gamma or cyber knife.
Radiation therapy treatment decisions for brain tumors are highly individualized and need to be made in the context of multidisciplinary planning.
Briefly stated, protons:
- Are more precise than conventional radiation therapy and do less damage to normal tissue
- Reduce side effects both short and long term
- Deliver slightly more radiation to the tumor on a dose by dose basis
- Are effective in treating tumors near sensitive structures such as the spinal cord
- Can be used to "retreat" some patients with brain cancers
He also noted that many patients encounter insurance issues in trying to get approval for proton therapy, although Medicare pays for most indications.
Stereotactic radiosurgery using the Gamma Knife® is another option for treating brain cancers. Michelle Alonso-Basanta, MD, PhD, assistant professor of radiation oncology, explained that the original Gamma Knife was not designed to treat cancers, but that advances in technology and technique have made this a useful therapy for some patients with brain cancers.
"As with protons," she says, "we can deliver a very high dose of radiation to the target with little or no exposure of normal tissue to the radiation. And, as with protons, the decision as to who will benefit from this approach is very individual."
Both stereotactic radiosurgery and protons offer the possibility of retreatment for patients who have undergone a previous course of radiation therapy and whose tumors have recurred. In the past, these patients were not eligible for additional radiation therapy.
Targeted Therapies: Changing Cancer Treatment
Penn Medicine has been a leader in immunotherapy research and in developing targeted vaccines for cancer for many years. Bruce Levine, PhD, facility director, clinical cell and vaccine production facility describes work currently underway that involves activating T-cells, one of the mainstays of the body's defense system, to fight cancers.
"If I could design T-cells to fight cancer," he says, "they would be potent, have a good memory, be persistent and numerous."
A new approach, developed at Penn, known as CAR (chimeric antigen receptor) T-cell therapy promises to be all of those things. CAR uses a complex process to remove cells from the patients and own body and activate them to attack the tumor. Penn is now in the process of developing clinical trials that will study the effects of CAR T cell therapy on glioblastomas with the EGRF v III mutation.
That mutation is the focus of work aimed at improving brain cancer treatment using chemotherapy as well. Arati Desai, MD, MAS, is using bevacizumab (Avastin), a drug that inhibits blood vessel formation, in combination with another drug in patients with recurrent glioblastomas. Phase II studies have demonstrated improved response rates and survival, although Desai acknowledges that some controversy exists about what those responses mean in terms of actual survival times.
Other clinical trials are aimed at attacking cancer cells from both the inside of the cell and the outside.
These include approaches using
- Immunotherapy
- Combinations of drugs that target multiple pathways
- Drugs that affect the environment around the tumor
- Drugs that block the critical M Tors pathway
- Drugs that target factors known to influence prognosis, such IDH1 and MGMT
"There isn't going to be a single drug or agent that is going to work for everyone," says Desai. "It's not going to be the same answer for every patient."
