The most common -- and unfortunately the most aggressive -- malignant tumor arising in the brain is the glioblastoma (GBM). And despite the advances made over the past decade in cancer therapy, the median survival from the time of diagnosis of this tumor remains at about 12 months.
Typically, treatment involves surgery to remove as much of the tumor as possible followed by a combination of radiation therapy and chemotherapy. Patients are often treated with steroids as well, in an effort to reduce brain swelling. These modalities have been shown to increase survival by only a few months compared to the choice of foregoing any medical treatment. Indeed, even with what most would consider the very best of currently available treatment, Senator Ted Kennedy succumbed to this type of brain tumor in just 15 months.
A fundamental premise in cancer therapy is trying to identify how the metabolism of cancer cells differs from normal tissue. When differences are identified, it often paves the way for treatments that will disrupt the cancer's metabolism while sparing normal tissue.
Recent discoveries have revealed an important difference between GBM cells and normal brain tissue. We've all learned that the brain depends upon an adequate supply of glucose -- its primary fuel -- to function appropriately. Interestingly, the human brain has developed an important backup plan when food is scarce. Humans are not the fastest or the strongest animals on the planet, but when it comes to survival we have had the unique advantage of being clever. Our ancestors relied upon their advanced brains to survive during times of food shortage and fortunately the human brain is able to utilize body fat as an extremely efficient fuel to sustain function when glucose providing food is unavailable. Essentially, the body breaks down fat to create ketones, a form of fat that readily and effectively powers the brain.
Recently, it was discovered that while normal brain tissue easily adapts to using ketones as a metabolic fuel, cancerous GBM cells lack this ability. This type of brain tumor depends almost entirely on a constant supply of glucose to thrive.
In a recent research publication, Dr. Thomas Seyfried from the Biology Department at Boston College, described a dietary modification designed to take advantage of the fact that GBM cells cannot thrive in a ketone rich environment while normal brain cells can. He proposed, "an alternative approach to brain cancer management that exploits the metabolic flexibility of normal cells at the expense of the genetically defective and metabolically challenged tumor cells."
Essentially, he described how a ketogenic diet would provide fuel for normal brain cells while profoundly reducing the glucose that the tumor cells required for survival. The fundamentals of this groundbreaking approach basically involve incorporating a low-carbohydrate diet like the popular Atkins approach, coupled with the addition of a nutritional supplement to provide extra ketones. For the latter, he described medium chain triglyceride (MCT) oil, a non-prescription supplement.
After his initial publication, aptly entitled, "Metabolic Management of Brain Cancer," Dr. Seyfried went on put his theory to the test. In April 2010 he published a report detailing his experience actually employing this approach in the treatment of a GBM patient. In this report, published in the journal Nutrition and Metabolism, Dr. Seyfried described the dramatic results achieved in treating a 65-year-old woman diagnosed with GBM who was treated with standard therapy including surgery, chemotherapy and radiation, as well as an aggressive ketogenic diet. The results were remarkable as the tumor regression far exceeded what would have been expected with standard therapy alone.
There are many reasons, some of which I suspect may be economic, that Western medicine settles on aggressive therapies like radiation and chemotherapy when confronted with the challenges of cancer. While nutritional approaches may seem less heroic or sophisticated, nonetheless when we see science-based ideas like those described by Dr. Seyfried, we owe it to our patients to pay attention.
While radiation and chemotherapy offer some degree of benefit, it's clear that their effectiveness in treating GBM is limited. The very best physicians can do is to remain open-minded.