Michael Garcia, MD
Neuro-Radiation Oncologist
As a radiation oncologist, Dr. Michael Garcia provides unparalleled precision and care to patients at the Ivy Brain Tumor Center at Barrow Neurological Institute. His expertise lies in the treatment of central nervous system tumors using non-invasive radiosurgery, stereotactic body radiation therapy (SBRT) and image-guided, intensity modulated radiation therapy (IMRT). He is board certified in radiation oncology by the American Board of Radiology.
As the author of numerous peer-reviewed articles in the areas of radiosurgery, medical education and patient symptom management, Dr. Garcia is a thought leader in his discipline.
He is the recipient of a long list of awards and honors including a Merit Award for research from the Conquer Cancer Foundation of the American Society of Clinical Oncology, the Linnane Scholar for academic excellence and community leadership from Harvard Medical School, and the Firestone Medal for top honors thesis at Stanford University.
Dr. Garcia earned undergraduate and graduate bioscience degrees at Stanford University. He received a medical degree from Harvard Medical School and completed a radiation oncology residency at the University of California – San Francisco.
Dr. Garcia’s interest in medicine began at an early age. When his mother was diagnosed with cervical cancer, the doctors that cared for her became his heroes.
Seeing the doctors and nurses come alongside his family and kindly walk them through that time made an impression. His close-knit family unfortunately experienced many cancer diagnoses. Those experiences gave him an affinity for medicine and led to his interest and career in radiation oncology.
Now, at the Ivy Center, Dr. Garcia strives to provide a superior level of care to his patients and their families.
“For each day, and each clinic visit, my goal is to help the patient and their family understand their diagnosis, feel comfortable with their upcoming treatments, feel well supported and listened to,” Dr. Garcia says. “At the end of each day, if I can look back at each person I met in clinic and see that I achieved these things, I count those days as successes.”
Q&A with Dr. Garcia:
What can patients expect during a typical radiation appointment?
There’s a lot of work done before the actual radiation appointment. I work with a team of physicists and dosimetrists to help me plan the radiation, which takes a week or two. We map the tumor and the normal anatomy of the brain and I work with the physicists on beam arrangement and dosing. Patients will wear a custom-made mask during radiation to keep the head perfectly still and the radiation machine rotates around the head to give different radiation beams at different angles. The radiation machine also has a CT scanner so it’s scanning the brain to make sure we are digitally aligned and the skull is lined up perfectly. The entire, painless procedure takes about 15 minutes. Patients can go back to work or go about their day afterwards.
How do you determine the type of radiation treatment for brain tumor patients?
The standard of care has been determined by clinical trials and sets the dose and number of fractions, or days of radiation. For example, for glioblastoma, that standard of care is to give 30 fractions of two gray each. A gray is a unit of radiation dose, just like a meter or an inch is a unit of distance. We give 60 gray over 30 fractions of two gray each. This is done over 30 treatment days or six business weeks. The patient comes in Monday-Friday to receive one fraction a day over those six weeks and each visit takes about 15 minutes.
That treatment regimen is based on many decades of literature. Studies and clinical trials have shown It’s the superior treatment and we’re trying to build on that at the Ivy Center. We’re trying to figure out if some drugs work better for some patients. All treatment decisions made at Barrow are evidence-based. Some of the modalities we use are unique to us. We’re the only Gamma Knife radiosurgery center in the state. We’re the first in the world to have the ZAP-X Gyroscopic Radiosurgery platform and the first center in the Southwest to have CyberKnife System.
What devices are used in radiation treatment for brain tumor patients?
Gamma Knife, ZAP-X and CyberKnife are all radiations. We treat glioblastoma patients with true beam or traditional linear radiation. In fact, they’re all photons, like x-rays and gamma rays. It’s all radiation, just different ways of dosing and giving the radiation but they’re all radiation beams.
How do radiation and chemotherapy work together?
Temozolomide, the current chemotherapy for brain cancer, makes tumor cells more sensitive to radiation. We’re trying to build on that at the Ivy Center through our Phase 0 clinical trials, to find new, more effective drugs. A major way that radiation works is by breaking down tumor cell DNA, and temozolomide helps with that breakdown. Radiation creates breaks in the DNA but glioblastoma has this super repair machinery that comes in and tries to fix the breaks. Damaged tumor cells cannot divide and will die. After radiation, the patient continues to take temozolomide, but at a higher dose.
What is methylated vs unmethylated MGMT?
We talk about methylation a lot. The MGMT gene fixes DNA breaks. When a patient has methylation, the methylation silences the MGMT and the MGMT can’t fix the DNA breaks caused by radiation and temozolomide. Unmethylated MGMT repairs DNA damage, undermining the work of radiation and chemotherapy. It’s kind of like a double negative. Patients with unmethylated MGMT may be a candidate for an Ivy Center Phase 0 clinical trial investigating a series of radiosensitizers that may enhance the effects of radiation.
Does radiation from treatment damage healthy cells?
Yes, anything in the radiation field is going to get DNA breaks. The brain can get injured by radiation. That’s why we break up the radiation dose into separate treatments, so the healthy cells have time to repair themselves in between treatments. Whereas the tumor cells, they don’t fix the damage in time so they begin to die off. That’s called fractionation and that’s the whole radio biological principle. The difference between our tumor cells and our normal cells is that our tumor cells are deranged so that, in general, they don’t have the same DNA repair mechanisms that our normal cells do. We’re exposed to radiation every day. Right now cosmic radiation is hitting us, I go outside and UV radiation is hitting me. We’re surrounded by forms of radiation. But our bodies and our normal cells have really good capabilities to fix DNA. Cancer cells don’t have that ability.
What are your goals as a neuro-oncologist in the next decade?
I’m grateful for the advances that are being made in the field of brain tumor research. I believe we are going to see major breakthroughs in the treatment of brain tumors, including gliomas – such as glioblastoma – brain metastases, and meningiomas. I hope to be involved in those breakthroughs. My goal is to help improve the outcomes of people with brain tumors, including helping these people to have better quality of life and live longer.