Question: I was recently diagnosed with lung cancer and am on my first line of treatment. I keep hearing that at some point I may develop a resistance to that treatment. What exactly does that mean and how long might I have before resistance develops?  

(Answered by Dr. Jyoti Malhorta by City of Hope Comprehensive Cancer Center during her appearance on the Lung Cancer Living Room. It has been edited slightly for this use.) 

Answer: When a patient is on a cancer treatment, many times it works for a certain period of time but for advanced lung cancer, we know that the treatment doesn’t work forever. At some point, the cancer cells will understand how they are being treated and they will learn a way to stop responding to that cancer treatment. That’s because the cancer cells do not stay the same. They divide and multiply—and during that process, they evolve and try to learn how to change to become resistant to the treatment they’re receiving.  

This can happen in many ways. The cancer cells can acquire a different mutation, a second mutation, or a change to their DNA; the cancer cells can find a way to stop being recognized by the immune cells; or the cancer cells can just learn how to get the chemotherapy out of their cells.  

There are so many ways resistance happens, and there’s really no way to predict how long it might take or what the mechanism of resistance might be. It can happen in different ways, at just one site, or at multiple tumor sites. It’s very heterogeneous in this way, and it’s something that we’re trying to understand through more research in this area.  

Although there is no way to predict what one person’s experience with resistance might be, there are some factors that we study that may give us a prognosis – things like if a patient has only one organ involved, compared to cancer which has spread to multiple areas, or if they have certain mutations which predict a shorter response to treatment. Hopefully, in the next five to 10 years, we can have very accurate models to predict how long the treatment will respond, so we can proactively prevent the emergence of resistance. For now, the best way to find resistance early is to do scans regularly while you’re in treatment. Regular scans help us identify development of resistance at a very early stage, and we can intervene and try to treat it early, rather than waiting until it has progressed to be more widespread. 

Please note that the information included in any published answer is for educational pursuit only and is not intended or implied to be a substitute for professional medical advice. The reader should always consult their healthcare provider to determine the appropriateness of the information for their own situation. Nothing from GO2 for Lung Cancer should be construed as an attempt to offer or render a medical opinion.