Abstract P3-06-11: Disease and treatment characteristics of a large insured female population with advanced or metastatic breast cancer by receipt of HER2-targeted agents
Authors: Hao Y , Landsman-Blumberg P , Meyer N , Johnson W , Willemann Rogerio J 
Published: August 2014

This retrospective administrative claims study of women diagnosed with advanced or metastatic breast cancer (BC) compared clinical histories and BC treatment by receipt of HER2- targeted agents (2TA), disease stage, and age group.

Women ≥ 18 years, diagnosed with stage III or IV BC were selected from the 2008-2012 Truven Health MarketScan databases using ICD-9-CM codes on non-diagnostic medical claims corresponding to BC and local or distant metastases; date of first metastasis was the index date. Patients were followed until the earliest of end of enrollment, inpatient death or 12/31/2012. Those with &lt;12 months continuous enrollment (CE) or non-BC primary cancers pre-index, or HIV or pregnancy anytime were excluded. 2TA was defined as ≥1 medical or pharmacy claim for trastuzumab or lapatinib in the pre- or post-index periods. Study cohorts were women ± 2TA use, 2TA users with stage III and IV BC, and 2TA users age 18-44, 45-64, or 65+ at index. Index demographics, pre-index BC and clinical histories, and post-index BC treatments were compared using t-tests, one-way ANOVA, and chi-square statistics.

Of 30,660 eligible women, 14.4% received 2TA at sometime. Compared to non-2TA patients those with 2TA were younger (mean (SD) age 55 (11) vs. 59 (13) years; p≤0.001) and had significantly lower comorbidity burden. While pre-index BC was similar (48% each), 2TA patients had higher rates of pre-index BC surgery (20% vs. 17%), adjuvant/neoadjuvent chemotherapy (74% vs. 53%), radiation treatment (12% vs. 10%), and lower non-2TA biologics use (0% vs. 3%), all p&lt;0.005. Of the 2TA cohort with pre-index BC, 58% used 2TA pre-index. Also among 2TA patients, 57% had Stage III BC at index and 18% were 18-44, 68% 45-64 and 15% 65+. Pre-index BC diagnosis differed by index BC stage (30% III vs. 73% IV) and increased with age (44% 18-44, 48% 45-64, 54% 65+), both p&lt;0.001.

Of those with ≥ 3 months CE post-index, 2TA users had higher rates, p&lt;0.001 of BC surgery (53% vs. 47%), radiation (65% vs. 54%) and non-2TA antineoplastic treatment (AT: 89% vs. 83%), compared to non-2TA patients. Of those treated, 2TA users had a higher rate of chemotherapy use (85% vs. 58%), but lower use rates of hormone therapy (56% vs. 78%) and non-2TA biologics (5% vs. 8%), all p&lt;0.001. Receipt of post-index BC surgery was greater among 2TA stage III than stage IV patients (78% vs. 19%) and decreased with age (62% 18-44, 53% 45-64, 42% 65+), both p&lt;0.001. Post-index, stage III 2TA patients were more likely (p&lt;0.001) to have radiation therapy (72% vs. 56%), use 2TA agents post-index (97% vs. 91%), and other AT (92% vs. 84%) compared to stage IV 2TA patients. Radiation declined in the 2TA cohort post-index with increasing age (70%, 65%, 61%, p&lt;0.001). 2TA and AT use also declined with increasing age but these did not reach statistical significance.

Receipt of 2TA (vs. non-2TA) was significantly associated with younger age and receipt of pre- and post- BC treatments. Clinical history and BC treatment differences between these cohorts partly reflect differential treatment patterns of HER2- positive and HER2- negative BC patients. Treatment characteristics for the 2TA cohort differ by disease stage and age group.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P3-06-11.