My mother used a cold cap when undergoing chemo during treatment for breast cancer. She kept her hair, although it thinned quite a bit, throughout treatment. She read about it extensively, understood that it is not as well accepted in the US, that it could carry additional risks, but the dignity (and hair!) that she retained during treatment was tremendous. I won't go into too many details, but I will say that she went through treatment and has gone more than two years without any reappearances of anything. She both caught it early enough (of course key) and had access to some of the best doctors available at Sloan Kettering.