Although there’s not a lot of proof that cannabis can directly fight cancer, there’s growing agreement among patients and oncologists that it offers powerful symptom relief for many people. In the Breastcancer.org survey, 75% of people with breast cancer who had tried cannabis said it was helpful. “Most of the survey responders wanted a solution to a side effect; they were not looking to get high,” says Breastcancer.org founder Marisa Weiss, MD, director of Breast Radiation Oncology at Lankenau Medical Center in Pennsylvania.