The impact of site of care (office clinic versus hospital outpatient) on treatment patterns in HER2-positive breast cancer.

e11077 Background: This study examines treatment (tx) patterns in patients (pts) with breast cancer (BC) receiving trastuzumab (T) in a physician clinic (MD) & outpatient hospital (HOSP) setting. Methods: Pts ≥18 yrs with BC (≥2 claims with ICD-9-CM 174.xx, ≥30 days apart) and ≥2 T claims from 1/1/2006 to 12/31/2010 were identified from a large US commercial insurance claims database. Pts continuously enrolled for ≥ 6mths before & after index date (date of 1st T claim) were included. Pts receiving T at both sites of care, receiving T before the index date &/or pts with > 1 primary cancer were excluded. Metastatic (mBC) vs. early stage (ESBC) tx was identified by presence of ≥2 claims of metastases after index date. Pts were followed from index date to 30 days after the last infusion prior to a gap of ≥ 90 days, death, disenrollment, or end of study period. Pts were stratified by site of care- MD or HOSP. Descriptive & multivariate analyses were conducted to examine differences in tx patterns (duration and...