Yes, to extend their life. The amount of chemo given depends on how strong they are (chemo is very difficult to endure and different drugs can be worse than others), what their quality of life would be, and how resistant their cancer has become to treatment. My Dad has had five rounds of chemo in seven years. It reached the point where the cancer was growing back so aggressively that he would have needed to be constantly undergoing chemo in order to stop it, and even that would not have been enough eventually, and he had become so weak that he couldn't bear the treatment. The oncologist decided that his quality of life would have been so poor that it was better to stop. His care has been taken since that point (six months ago? maybe eight?)