Prevalence and Safety of Off-Label Use of Chemotherapeutic Agents in Older Patients With Breast Cancer: Estimates From SEER-Medicare Data

Off-label use without scientific support was not common, whereas 64% of use was off-label/supported, reflecting the fact that widely accepted indications are often not tested in registration trials. Off-label/supported use will likely increase as more drugs are expected to have activity across cancer sites, and therefore understanding the implications of such use is critical.