The Changing Landscape of Cancer Treatment
Posted on March 5, 2013
Mark Mainwaring, MD, for Nashville Health and Wellness Magazine
What makes a person to want to be a cancer doctor? Aside from special motivation, dedication and lifetime commitment is the fact that some of the most exciting developments in the science of medicine are now changing the attitude, outcome and longevity of individuals with cancer. The change is not restricted to individuals with cancer but whole families, neighbors, friends and colleagues. This influence carries over to diverse associations including but not exclusive to university teaching institutions, drug manufacturers, and even corporate America. The primal desire to better identify, treat, control and cure cancer is in everyone. How this effort is taking shape is finally becoming clearer: more specific curative treatment with less pain and suffering.
Over the last 20 years there have been more changes in medical oncology than any other branch of medicine. Previously, chemotherapy was our only weapon against almost all solid and blood cancers. But starting about 15 years ago, the biology of cancer growth started to reveal its secrets, and treatment schemes unfolded that have progressively eliminated the use of chemotherapy.
One milestone in particular was treatment of an aggressive blood cancer, Acute Promyelogenous Leukemia (APL). This subtype of acute leukemia used to be fatal in greater than 80% of cases. Cancer researchers however, found that an APL cell could be re-programmed to grow back to a normal white blood cell using a simple derivative of Vitamin A. The use of small molecules, such as modified vitamin A to specifically affect cancer signals introduced the concept of ‘biological therapy’. Instead of using toxic chemicals (chemotherapy) with the hope of poisoning cancer, the goal of biological therapy is to find that ‘magic bullet’ that specifically identifies and kills only cancer cells with little or no collateral damage. The treatment of APL using a modified vitamin A molecule (ATRA- all trans-retinoic acid) in addition to chemotherapy, now cures over 90% of patients with this ‘ugly’ leukemia.
The secrets of the signals in the cell that cause and sustain cancer growth are slowly being revealed by intensive, painstaking and focused medical research. Unfortunately, human cancers are diverse in that there is not any single common cellular mistake that can drive all cancers to grow. Capturing the specific abnormality of each cancer, such as colon cancer or breast cancer, and designing molecules (not chemicals) that reverse that cellular mistake are no longer just a concept ideas. With the discovery of specific cell signals driving different types of cancer growth, hundreds of new molecules or proteins engineered in the laboratory are being tested to control specific cancers.
As an example, recently, a 62 year old gentleman came to my office and was identified with a very high white blood cell count, an anemia (low red blood cells) and dangerously low platelets (blood element that starts blood clots). His diagnosis was Chronic Myelogenous Leukemia (CML). Ten years ago, he would have been treated with chemotherapy which was not very effective in controlling this disease, and rarely cured it. Today however, the specific genetic abnormality causing CML has not only been identified but that abnormal signal can be changed using a simple but very specific engineered protein. Two weeks after this gentleman started taking this ‘protein’ once a day, (Gleevec/ Imatinib) he had normal blood: WBC normalized, anemia cured and normal platelet count. His CML disease is still there and although he is not cured, he will only require taking this pill once a day until an absolute cure can be discovered. His blood counts will remain normal and he has, and never will, receive chemotherapy to control this ugly leukemia.
‘Biological treatment’ is now under investigation for every type of cancer. There have been some miraculous responses with this approach. Cancer previously uncontrolled by standard chemotherapy is increasingly responsive to new specific biologic therapy. The challenge in the future will be to individualize biological treatment for each and every cancer in adults and children. This must be achieved at an affordable cost and available to everyone whom has developed this overwhelming disease. The day of never using chemotherapy again to control cancer is rapidly nearing. Biological therapy will be the standard of care, and with it, the elimination of the pain and suffering associated with this disease. Thankfully that day is rapidly approaching.