Those who have cancer, along with their family and friends, have been searching anything that’s available to find the best possible way to beat the disease. Things like “personalized medicine,” “precision medicine,” or “targeted drugs” are things you have likely seen. But are these things that can help you, and exactly what are they? Precision medicine is also called pharmacogenetics and a new way of fighting cancer by taking information about you and your tumor to decide what’s driving the disease and then strives to create a plan specifically for you.
Cancer treatment has been a cookie-cutter process for years where surgery would be chosen to remove a tumor, then chemo or radiation was used to kill the cancer cells. Blasting the cancers with chemotherapy or radiation kills the healthy cells as well and can most likely lead to a host of really nasty side effects. The researchers now have the ability to examine your cancer cells and learn the order of the genes in their DNA. Most of the cells in the body have identical genes. Those in cancer cells have mutation or changes and this allows them to grow into tumors.
Someone else’s cancer may have different genetic changes than yours and the scientists know that genetically, one person’s breast cancer may be more similar to another person’s stomach tumor than to other breast cancers. This makes having personalized medicine an even greater need.
More than a dozen drugs that target one of these mutations has been approved by the FDA. Imatinib (Gleevec), a drug used on chronic myelogenous leukemia, and the breast cancer drugs trastuzumab (Herceptin), are included. Doctors learn which drugs won’t work from the tumor genetics. As an example you won’t be given two colon drugs if your cancer has a genetic mutation called KRAS, as they know they won’t work. Tumor profiling is also performed in many clinical centers where the doctor takes a look at your tumor’s genes. If your cancer might have specific mutations, your doctor might start you on a specific drug that’s approved for your type of cancer. Otherwise, a genetic test would tell him in a certain drug might work for you. This genetic profiling can help if other treatment options haven’t worked for you. The genetic mutation could point the medical team toward an unexpected drug like one that was originally designed for another type of cancer.
This is not a magic bullet but the personalized approach works better to shrink tumors and save lives than the traditional treatment, but is not always a cure. Cells with different gene mutations can appear in tumors, so a targeted therapy designed to pick off cells with one mutation may work on only part of a tumor while the other cells may keep growing.
There are some trials available to test cancer treatments using people whose tumors are similar in size or location. Only those with stage IV lung cancer might be chosen, but now that there is personalized medicine, the researchers now need ways to study how targeted treatments work on a variety of cancers. Creating new treatments require a constant effort between doctors and scientists. After new drugs are made to combat the new gene changes, they are tested in the clinic. More drugs will become available as tumors change in new ways.
Dr Fredda Branyon