I heard that radiation can cause cancer. Will it increase my risk for others?

Yes but not much. It's still the right answer, almost always. Radiation treatments have been shown to slightly increase the risk of leukemia, thyroid cancer, early-onset breast cancer, and some other cancers. But those risks are far outweighed by the benefits of radiation to prevent recurrence of many cancers, and even cure some of them. Your oncologist knows best! take his/her advice!