Therapeutic Options For Cancer Patients In 2011
The field of oncology is a relatively new field. As a matter of fact it was not until the mid to late 1940's that the idea of treating cancer with drugs was entertained. Sydney Farber, a trained pathologist at Harvard who could not bear to continue performing autopsies on children with leukemia had the idea of using antifolate agents to stop the growth of the abnormal white blood cells. This was the beginning of chemotherapy.
Chemotherapy works by damaging deoxyribonucleic acid (DNA) and ribonucleic acid (RNA) in rapidly dividing cells, it therefore is not specific only to cancer cells but affects also the “normal” cells in the body that are continuously dividing like white blood count/red blood count/hair/gastrointestinal mucosa/platelets/nails.
As better understanding of the biology of tumors has occurred we are moving more and more toward “targeted” treatments. The very first targeted therapy that was developed was in fact tamoxifen, a drug that binds specifically to the estrogen receptors that drive some breast cancer cell growth. This drug was followed by the development of numerous other selective serotonin reuptake inhibitors (SSRI's) and also aromatase inhibitors which shut off the production of estrogen by specifically blocking the enzyme aromatase.
By focusing more on what drives the incessant cell growth in cancers, numerous pathways have been identified that are used as therapeutic targets and new classes of drugs have been developed with better results and less toxicity including monoclonal antibodies, antiangiogenic drugs, tyrosine kinase inhibitors, protasome inhibitors. It is now possible to cure CML with tyrosine kinase inhibitors (oral medications) like gleevec, spricel and tasigna. It is possible to treat metastatic colon cancer very successfully with combination therapies that do not include chemotherapy like erbitux (which is a monoclonal antibody) and avastin (an antiangiogenic agent) with less side effects and no bone marrow suppression.
Proteasome inhibitors and antiangiogenic agents like revlimid (oral) and velcade are now being used first line and second line in myeloma patients.
Monoclonal antibodies and tyrosine kynase inhibitors like herceptin and tykerb respectively, have more than doubled the survival and cure rate of her2/neu positive breast cancer patients.
Renal cell cancer notoriously not responsive to chemotherapy has now numerous therapeutic options including tyrosine kinase inhibitors antiangiogenic agents and mTOR inhibitors like sorafenib, sunitinib, torisel, avastin and everolimus to name a few.
Genomic profiling of cancers will further shed light on additional therapeutic targets that in time will be more effective and specific. Slowly but surely cancer is being turned into a chronic disease.