Drug shortages have become more frequent and may lead to delays in treatment or failure to deliver the appropriate drug, an error of omission. This secondary data analysis examined how oncology drug shortages affected use of chemotherapy medications among patients with newly diagnosed cancer as measured by Medicare claims data. The changes in utilization varied by medication; overall, drug shortages had only a modest impact on the delivery of these drugs to patients with newly diagnosed cancer. This finding contrasts with a prior study showing patient harm related to drug shortages, and the authors recommend further study to understand how to identify and mitigate clinically relevant drug shortages. A WebM&M commentary discussed strategies for preventing or minimizing adverse events associated with drug shortages.