Immunotherapy a new hope for treatment
Originally published in the Bloomington Pantagraph on 10/9/18
Immunotherapy is a newer type of cancer treatment which uses our body’s defense system to fight cancer.Our immune system not only protects us against common cold and pneumonia. It also protects us against cancer.
The cells of our immune system are constantly monitoring our body for cancer cells. We have many different types of defensive immune cells such as natural killer cells, dendritic cells and T cells. Once these cells find the cancer, they send signals to their partners and they work together to destroy the cancer cells.
Unfortunately, this is not a foolproof system. In some patients, the cancer cells get smarter and escape this attack. At times, cancer cells may even start to retaliate and attack our immune cells.
The cancer cells use many different tricks to beat our immune system. One such trick is called the immune checkpoint. In this process, the cancer cells forcibly engage brakes in our immune system. They shut it down by deactivating the T cells. The T cell is like a tank that is moving toward the enemy line, in this case, the cancer cell. By engaging the immune checkpoint, the cancer cells apply the brakes on the T cells. Once the brakes are on, our tank is stuck in its tracks. It cannot move and it cannot fire. It has been deactivated and the cancer continues to grow.
Over the past decade, we have learned a lot about these checkpoint interactions. One such interaction is between the PD-1/PDL-1 molecules. We have been able to utilize this knowledge to develop newer medications that remove the brakes from the T cells and help to activate these sleepy or deactivated T cells. These medications include ipilimumab (Yervoy), pembrolizumab (Keytruda), nivolumab (Opdivo), atezolizumab (Tecentriq), avelumab (Bavencio) and durvalumab (Imfi nzi). There are
several more in the works. We have been using these medications in the treatment of lung cancer, melanoma, bladder cancer and some rare cancers.
What about breast cancer and immunotherapy? This is the new frontier of cancer research. As of now, we do not have any FDA-approved breast cancer immunotherapies. However, within the past few years, there has been a lot of exciting research in this field. We have a better understanding of the breast cancer and immune system interaction. As it turns out, there is a specific type of breast cancer called triple negative breast cancer (these breast cancer cells do not have estrogen,
progesterone or the Her2/neureceptors) in which immunotherapy is very active.
There are several ongoing research trials that are looking at immunotherapy in triple negative and other types of breast cancer. In years to come, immunotherapy will continue to evolve as its role in breast cancer is rapidly developing. Immunotherapy is making a real and meaningful difference in the lives of our patients by improving
their treatment options.