Why is Brain Cancer so Difficult to Treat?
The sudden death of Beau Biden, son of U.S. Vice-President Joe Biden, over this past weekend has been garnering international attention and awareness to brain cancer. According to the National Cancer Institute, brain cancer is defined as, “a disease where abnormal cells form in brain tissue”. The NCI also notes that the five year survival rate for someone diagnosed with brain cancer is only 33.3%. Rather than providing a comprehensive overview of brain cancer, let's discuss why the survival rate is so low. In addition, some new and promising brain cancer treatments will be discussed towards the end.
First, we need to look at the causes of brain cancer. Because the cause of most brain tumors is unknown, it is difficult to suggest anything preventative. This is because there is a lack of consistency of presentable symptoms in brain cancer patients. For example, some people may experience seizures (as was the case of Beau Biden), while others may experience abnormal headaches.
Despite this variability, if some signs are observed (see this Recnac post for more details), doctors use a series of diagnostic tests to determine if the neurological issue is brain cancer or not. These include but are not limited to: a physical exam, a neurological exam, a tumor marker test, a CT scan, an MRI, and genetic testing. If signs of a tumor are seen, then physicians resort to a biopsy, which is where they remove a piece of abnormal tissue. The tissue is then examined by a pathologist to determine if the mass is cancerous or not. This can be done in two ways: stereotactic and open. Because the brain is extremely sensitive, doctors are very careful in how they approach neuro-oncology cases. In a stereotactic biopsy, which is more recent, a computer/3-D scanner is used to see precisely where the mass is. Once the mass is localized via the 3-D scanner, the surgeon will drill the skull via a small incision and extract a piece of tissue. Because it is a pinhole size, the recovery time is relatively fast. In an open biopsy, a craniotomy is performed where the incision and drilling of the skull is significantly larger. Sometimes, if the results come back as cancerous, the neurosurgeon will remove as much of the neoplasmic tissue as possible then and there. In the case of Beau Biden, the neurosurgical team was successful in excising the cancer two years ago at MD Anderson in Texas.
However, another major issue in brain cancer treatment that affects the survival rate is the precious “real-estate” of the brain. Although surgery is the primary method of treating brain cancer, there are certain areas of the brain where surgeons cannot excise a tumor because it can severely debilitate the patient. As a result, sometimes, a “watchful waiting” approach has to be implemented. In this case, neurologists, oncologists, and neurosurgeons monitor the patients carefully without any intervention. This is done until there is a change in signs or symptoms. In addition to this approach, because of the “real-estate” sometimes surgery cannot be the only treatment. Instead, chemotherapy and/or radiation must follow the surgery. Both these methods of treatment do have side effects which include but is not limited to trouble with memory and speech. Thus, while it helps treat the cancer itself, the side effects are significant.
Currently, there are clinical trials for two new methods of treatment for patients diagnosed with brain cancer. The first is in the field of radiation oncology and involves proton beam therapy. In this case, hydrogen ions (the positively charged form of hydrogen, commonly known as a proton) are extracted from water molecules. These protons are compiled to make radiation. Then, the proton beam attacks the tumor at a localized level without damaging surrounding tissue. Please note that there is a difference between proton beam therapy and x-ray radiation therapy. The dosage of proton therapy required to target a tumor is significantly less than x-ray radiation therapy, which results in a more optimum outcome. Second, immunotherapy shows some promise and is undergoing clinical trials. According to the NCI, it is being tested for certain types of brain tumors, and frequently involves dendritic cell vaccine therapy and gene therapy.
In conclusion, the reason brain cancer is so difficult to treat is multifold. As a result, the only way to increase the survival rate is a multi-tiered approach. First, scientific and medical researchers are carefully studying patients who have brain tumors to try and zero in on more specific symptoms. Although the lack of consistency is present, hopefully studies that include a larger population size will be able to provide better answers. Second, ongoing innovation in neuro-oncology diagnostics needs to take place. The earlier a brain tumor can be detected, the easier and less aggressive the treatment, which means a hopefully better outcome for patients. Third, continued research in methods analogous to stereotactic radiosurgery need to take place. The use of stereotaxy changed the way neurosurgeons biopsy brain tumors. As long as scientific and medical researchers continue to improve on current surgical techniques to incorporate a more minimally-invasive approach, the patient outcome will hopefully improve. Fourth, the techniques that are undergoing clinical trials need to continue so we can learn better ways to treat brain cancer. Finally, the genetics of brain cancer, if any, need to be analyzed more closely and scientifically studied more in depth. If we can determine certain genetic predispositions that lead to brain cancer, it will change our understanding and potentially our treatment of this deadly disease. Only after all of these aspects of brain tumor care are addressed could we even begin to think about prevention. The challenges are great, but with the vast resources we have, we can hopefully see better outcomes in our lifetime.
Please join me in sending our deepest condolences to the Biden family during this difficult time.
About SC Ali
S.C. Ali is an author/editor. He has a degree in Chemistry, and is interested in the study and practice of medicine. His blog can be found here: http://thebronzelifestyle.com/