More than eight in 10 U.S. cancer specialists have struggled to find the drugs they need to best treat their patients, a new survey has found. Such drug shortages could affect people with colon cancer, breast cancer and leukemia. They include chemotherapy drugs prescribed after a tumor has spread. "These are drugs used for common and curable cancers," Dr. Keerthi Gogineni of the Hospital of the University of Pennsylvania in Philadelphia told Reuters Health. "It is becoming increasingly difficult for patients with cancer to receive the lifesaving treatments they need," she and her colleagues write in a letter published in the New England Journal of Medicine.