Does radiotherapy or chemotherapy make hair fall out?

The reason that chemotherapy makes your hair fall out is that the current chemotherapy treatments we have are very aggressive drugs. They kill cells that are growing fast. This usually means cancer cells, which grow quickly, but also your skin cells, your hair cells and your gut cells are all growing quickly. They are also affected by the drugs, and that's why you get side effects such as feeling sick and your hair falling out. Hopefully some of the new treatments that Fran and people are working on are going to be much more targeted and only hit cancer cells and not the other cells.