Pursuant to a congressional request, GAO provided information about its survey of a nationally representative sample of oncologists to determine the extent to which health insurers denied patients reimbursement for off-label drug use, focusing on: (1) the prevalence of off-label drug use, and how its use varied by clinical, demographic, and geographic factors; (2) the extent to which third-party payers denied payment for such use; and (3) whether third-party payers’ policies influenced the treatment of cancer patients. GAO presented a copy of the questionnaire it mailed to the random sample of oncologists, with the number or percentage of respondents answering each item. GAO noted that it received a 56-percent response rate to its mailing of 1,470 questionnaires.