Prevalence and safety of off-label use of chemotherapeutic agents in older patients with breast cancer: Estimates from seer-medicare data

Background: Prescribing drugs outside of the label indication is legal and may reflect standard practice; however, some off-label use may be inappropriate. This study measured the prevalence and safety of off-label use both in accordance with practice guidelines and inconsistent with practice guidelines in older patients with breast cancer. Patients and Methods: The SEER-Medicare data set was used to identify women diagnosed with breast cancer. Intravenous chemotherapy was identified using Medicare claims and classified as either on-label, off-label but included in the NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Breast Cancer ("off-label/supported"). Or Off-label and Not Included in the NCCN Guidelines . Hospitalization/emergency Dept. Admission Rates Were Compared. Results: A Total of 13,347 Women Were Treated with 16,127 Regimens ; 64% of Regimens Were Off-label/supported, 25% Were On-label, and 11% Were Off-label/unsupported, and Hospitalization/ED Admission Occurred in 27%, 25%, and 32% of Regimens, Respectively . Drugs Never Included in the NCCN Guidelines for Breast Cancer Accounted for 19% of Off-label/unsupported Use . Conclusions: Off-label Use Without Sci. Support Was Not Com., 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 Activ. Across Cancer Sites, and Therefore Understanding the Implications of Such Use Is Critical.