Abstract P5-08-15: Real-world treatment patterns and survival among triple negative breast cancer patients versus patients with other breast cancer subtypes in early stage breast cancer
Authors: DaCosta Byfield S , Abushamaa AM , Becker LK , Shepherd SP , Ricker JL , Bonnet P 
Published: March 2017

Background: It is generally accepted that outcomes of breast cancer (BC) patients (pts) differ by tumor characteristics, but relatively few studies have examined treatment patterns and outcomes in early stage disease by hormone receptor (HR) and HER2 status.

Methods: This retrospective study used physician-reported clinical information (date and stage at diagnosis, HER2 and HR status) for commercially insured BC pts from the Optum Oncology Management Registry linked with the Optum Research Database (medical and pharmacy claims from a national US health plan) and death data from Social Security Administration files from 01/2008 to 6/2014. Pts diagnosed with early stage breast cancer (ESBC) were examined. The index date was diagnosis of BC. Adult pts (≥18 yrs old) had to have known HR and HER2 status, continuous enrollment in the health plan from initial diagnosis for ≥6 months, surgery and systemic cancer therapy. Neo-adjuvant and adjuvant therapy (initial phase of care) based on timing of claims for NCCN-recommended therapy were examined, as well as survival and development of metastasis (based on claims with ICD-9 codes 196.0x, 196.2x, 196.5x-199.0x) after initial phase of care during the study period. Differences across the HR/HER2 subtypes were examined using t-test for continuous variables and chi-square test for categorical variables.

Results: Among 6,881 ESBC pts identified, 15% (n=1038) were TNBC pts, 65% HR+/HER2-, 14% HR+/HER2+ and 6% HR-/HER2+. Mean (median) age was 52 (53) years. Treatment patterns and outcomes vary by tumor subtype (Table).

 HR-/HER2-HR+/HER2-HR-/HER2+HR+/HER2+ N=1038N=4452N=401N=990Length of follow-up, mths, mean(SD)*, median27 (16), 2328 (16), 2529 (16), 2527 (15), 24Length of initial phase of care – mths, mean(SD)*, media10 (7), 922 (15), 1915 (9), 1423 (14), 19Pts with systemic neo-adjuvant therapy N (%)*303 (29)531 (12)140 (35)216 (22)Most common neo-adjuvant regimens (%)Paclitaxel, cyclophosphamide, doxorubicin (45%)Paclitaxel, cyclophosphamide, doxorubicin (31%)Docetaxel, carboplatin, trastuzumab (44%)Docetaxel, carboplatin, trastuzumab (31%)Pts with systemic adjuvant therapy N (%)*740 (71)4065 (91)366 (91)935 (94)Most common adjuvant regimens (%)Paclitaxel, cyclophosphamide, doxorubicin (30%)Tamoxifen (19%)Docetaxel, carboplatin, trastuzumab (30%)Docetaxel, carboplatin, trastuzumab, tamoxifen (9%)Evidence of distant metastasis N (%)*78 (7.5)76 (1.7)17 (4.2)15 (1.5)Mortality N (%)*23(2.2)23 (0.5)1 (0.3)3 (0.3)*p&lt;0.05

Conclusions: The most common neo-adjuvant and adjuvant chemotherapy agents received were similar across HER2 subtypes and regimens for HR+ and HER2+ patients also included hormonal or HER2 targeted agents. TNBC pts had the shortest length of initial phase of care (mean 10 mths), though this cohort had the second highest percentage of patients receiving systemic neo-adjuvant therapy. Development of distant metastasis and mortality during the study period were highest for the HR-/HER2- patients, at 7.5% and 2.2% respectively. Development of novel targets and therapies for TNBC may significantly benefit patients with this BC subtype, in both neo-adjuvant and adjuvant setting to improve outcomes.

Citation Format: DaCosta Byfield S, Abushamaa AM, Becker LK, Shepherd SP, Ricker JL, Bonnet P. Real-world treatment patterns and survival among triple negative breast cancer patients versus patients with other breast cancer subtypes in early stage breast cancer [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P5-08-15.