Abstract P5-08-24: How do real-world treatment patterns compare to guideline recommendations for first-line metastatic breast cancer patients in US community clinics?
Authors: Chu L , Yoo B , Carrigan G , Lai C , Beattie M , Reyes C 
Published: March 2017

Abstract
Background:
Treatment (txt) guidelines are based on trial data from a small minority of patients (pts). Linked electronic health records (EHRs) are a novel approach to examine txt patterns and outcomes in larger and more generalizable populations. Given the increasing importance of real world data and real world outcomes, we utilized linked EHRs from a network of US community clinics to examine how real world txt patterns compare to metastatic breast cancer (mBC) txt guideline recommendations.
Methods:
The Flatiron database provides real world clinical data collected from EHRs used by US cancer care providers. The Flatiron network comprises ~15% of US cancer pts and is geographically and demographically diverse.
Using EHR from Jan 2016 mBC database, we evaluated first-line (1L) txt patterns in mBC by molecular subtype. Pts were selected if they received mBC txt within 60 days of mBC diagnosis between 01Jan2011-31Dec2015, had ≥2 visits within the Flatiron Network on or after 01Jan2013, and were ≥18 years (yrs). Analyses were conducted to describe pt and clinical characteristics and 1L txt by HER2 and/or hormone receptor (HR) status.
Results:
Among 2509 mBC pts identified, 58.9% were HR+/HER2-, 17.7% HER2+, 11.6% HR-/HER2- (triple negative, TNBC), 7.4% HER2 equivocal, and 4.3% 'not done/unknown HER2 status'. Txt patterns in the latter two groups were not analyzed. Selected pt and disease characteristics by subtype are shown in Table 1. Median follow-up since mBC diagnosis was 1.1 yrs (range 0-5 yrs). The 1L mBC txts by subtype are shown in Table 2. Pts with HR+/HER2- subtype were treated primarily with hormonal therapy (68%) and/or chemotherapy (chemo) (35%). Among HER2+ pts, the 1L mBC txt patterns include trastuzumab+pertuzumab with chemo (31%), trastuzumab with chemo (22%), trastuzumab with hormonal therapy (9%), ado-trastuzumab (4%), lapatinib with chemo (3%), and lapatinib with hormonal therapy (1%). For TNBC, the majority received chemo (95%), such as paclitaxel (21%), nab-paclitaxel (13%) and docetaxel (12%).
Conclusion:
This study advances our current understanding of real world 1L patterns of care by molecular subtype among mBC pts and how these compare to guideline recommendations. While the majority of pts are receiving therapy per guidelines, up to 22% of HER2+ of pts are not receiving targeted therapy in 1L mBC
Table 1. Patient and disease characteristics by subtypeN (%)HR+/HER2- (N=1479)HER2+ (N=445)TNBC (N=291)Age at mBC diagnosis (yrs), median (range)66 (24-85)60 (27-85)60 (33-85)Sex Female1459 (99)441 (99)289 (99)Race White995 (67)274 (62)168 (58)Black112 (8)44 (10)42 (14)Asian19 (1)14 (3)5 (2)Other179 (12)50 (11)36 (12)Missing173 (12)63 (14)40 (14)MBC type De novo418 (28)172 (39)94 (32)Recurrent881 (60)225 (51)178 (61)Unknown180 (12)48 (11)19 (7)HR Status Positive1479 (100)300 (67)--Negative--145 (33)291 (100)
Table 2. 1L mBC treatments by subtypeN (%)HR+/HER2- (N=1479)HER2+ (N=445)TNBC (N=291)Any Targeted Therapy*77 (5)346 (78)12 (4)Any Chemotherapy521 (35)283 (64)276 (95)Any Hormonal Therapy1010 (68)115 (26)16 (6)*Targeted therapy includes trastuzumab, pertuzumab, ado-trastuzumab emtansine, lapatinib and bevacizumab
Citation Format: Chu L, Yoo B, Carrigan G, Lai C, Beattie M, Reyes C. How do real-world treatment patterns compare to guideline recommendations for first-line metastatic breast cancer patients in US community clinics? [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 P5-08-24.