Background: Drug shortages of common chemotherapeutics have been reported.What is the prevalence and consequence of these shortages? Methods: Between 9/2012 and 1/2013,a self-administered questionnaire was sent to a random sample of 455 board-certified U.S.oncologists selected from the American Society of Clinical Oncology directory to assess the prevalence of shortages and impact on therapeutic decision-making.245 responses were received(response rate 55%),of whom 210 were practicing medical oncologists/hematologists.Results: Due to drug shortages in the prior 6 months,92%(163)of oncologists reported that their patients treatment was affected and 83%(174)were unable to prescribe standard chemotherapy.The five chemotherapy agents most commonly reported in shortage were: leucovorin(68%),liposomal doxorubicin(63%),5-FU(19%),bleomycin(18%),and cytarabine(17%).Physicians adapted in many ways.38%of the time,oncologists substituted more expensive branded drugs for those in shortage,such as levoleucovorin for leucovorin.Nearly 13%of the time,shortages prevented enrollment,delayed administration of a study drug,or suspended involvement of patients on clinical trials.Despite the prevalence of scarcities,70%(146)of oncologists reported their cancer centers or practices lacked formal guidance for allocation decisions.Conclusions: Drug shortages in oncology are very common,compromise the delivery of standard care,impede research,and lead to higher costs by using branded drugs instead of generics.Oncologists also seem to lack formal guidance on how to address these shortages.