Can cancer become resistant to targeted therapy?

Yes. Cancer cells can become resistant to targeted therapy.

Resistance can happen in two main ways. Sometimes the target itself changes, so the targeted therapy can no longer interact with it. Other times, the cancer cells find new ways to grow that do not depend on the target at all.

Because of resistance, targeted therapy may work best when it is used with more than one type of targeted therapy or combined with other cancer treatments, such as chemotherapy and radiation.

Resistance is one reason your care team watches how the treatment is working over time, using exams, blood tests, and scans. If a targeted therapy stops working, they can talk with you about other options.