A handful of San Francisco breast cancer patients are donning frigid skullcaps to test a device designed to keep hair tightly rooted during chemotherapy. Researchers hope the study, run by UC San Francisco and Wake Forest University in Winston-Salem, NC, will eventually lead to Food and Drug Administration approval for the chilly caps. There is now no way to hang on to one's tresses during chemo for any kind of cancer, says study leader Hope Rugo, an oncologist at UCSF. The prospect of baldness is distressing to many patients, particularly women. Some choose a less-drastic drug regimen more likely to leave hair follicles alone, potentially at the cost of getting the best possible treatment. The caps' low temperature, 41 degrees Fahrenheit, keeps poisonous chemotherapy drugs out of the hair follicles. But some doctors worry that in so doing, it makes it more likely that cancer will take root in the scalp.