Lorraine Heidke-McCartin, 54, has experienced heartening victories and wrenching setbacks in her fight with breast cancer. Last summer, her hopes were buoyed when her doctors said she was a good candidate to take a promising experimental drug at Boston's Dana-Farber Cancer Institute. The treatment, called T-DM1, had reduced patients' tumors -- with few side effects -- during clinical trials. But in late August, shortly before the treatments were to start under a so-called expanded access program, the drug's maker, the Genentech division of Roche Holding AG, shut down the program in Boston after the Food and Drug Administration refused to speed the approval process. The about-face underscores the plight of thousands of patients whose lives can be thrown into upheaval by decisions about who can receive experimental drugs. Desperate to regain their health, they might be willing to try almost any treatment, even if it is unproven.