It can. The chemo also kills the cells in the stomach and digestive tract. Most people dont really loose complete control, but will have bad diareah and wont be able to hold it, like you will be running to the bathroom as fast as you can. And I am willing to bet that most of us here have had that happen. I myself was walking in the hall at the hosp in short short pj shorts when I suddenly had diareah all over me. lol. I just felt something on my leg and was like, what is that. I reached down to see, and then I saw alright!!!
If you do loose control, or start getting diareah, dont worry too much about it. Make sure your doc knows, though. They may want to culture the stool to make sure you dont have an infection. You may also want to consider switching from toilet paper to baby wipes. Its easier on the skin. You should regain control as your body heals from the chemo.