Treatment patterns and associated adverse events among patients with metastatic triple-negative breast cancer.
e12576 Background: Triple-negative breast cancer (TNBC) accounts for 10–20% of all breast cancers and about 4% are metastatic (mTNBC) at diagnosis. This research aims to describe treatment patterns and associated adverse events (AEs) among mTNBC patients. Methods: MarketScan Commercial Claims and Encounters and Medicare Supplemental Database, linked to an oncology EMR database, was used to identify patients with mTNBC. Demographic factors, clinical characteristics, mTNBC treatment patterns (treatment type and initial regimen), and the incidence of associated AEs (rates per 100 person-years) were tabulated. Patients seen in oncology practices between January 1, 2011 and June 30, 2015 were included in the study and were required to have continuous enrollment overlap in the administrative claims data for 6 months before the first diagnosis and throughout the variable-length follow-up period. Follow-up ended due to death, end of continuous enrollment, or end of study (whichever occurred earlier). Results: The study identified 163 mTNBC patients with a mean age of 55 years. The average length of follow-up was 569 days and 34% died during the study period. Diabetes mellitus (22%) and anemia (16%) were the most common comorbid conditions at baseline. During the follow-up period, the majority of mTNBC patients received treatment (76%); the most common first-line treatments included cyclophosphamide (60%), paclitaxel (56%), doxorubicin (52%), carboplatin (25%), and docetaxel (23%), averaging 96 days in duration. In 47% of patients, treatment ended due to a switch. Over 96% of the patients experienced at least one AE during treatment, the most common being hematological (neutropenia, leukopenia, and anemia), gastrointestinal (nausea and vomiting), and other (pyrexia, fatigue, and dyspnea) [see table]. Conclusions: Several different chemotherapy agents were used to treat mTNBC. Adverse events were common among mTNBC patients initially treated with chemotherapy; the highest incident AEs were hematological. [Table: see text]