A Genentech drug received federal approval on Friday to treat breast cancer, a surprise decision that could represent a shift in standards for assessing the effectiveness of cancer medicines. Going against the recommendation of its advisory panel, the FDA judged the effectiveness of Avastin based on measurements of tumor growth, not patient survival. The ruling prompted a mixed reaction from doctors and advocates for breast-cancer patients. Some bemoaned the lowering of medical standards, but others applauded the federal government's endorsement of a drug that is already prescribed "off-label" to an estimated 9,500 patients and for whom insurance coverage is limited.