Abstract P5-08-19: Treatment patterns and resource utilization among elderly Medicare patients with HR+/HER2– metastatic breast cancer
Authors: Goyal RK , Carter GC , Nagar SN , Smyth EN , Price GL , Huang Y-J , Bromund JL , Li L , Schilder JM , Davis KL , Kaye JA 
Published: March 2017

Abstract
Background
Therapeutic advances in metastatic breast cancer (MBC) over the last decade have led to several novel agents for the treatment of patients with hormone receptor positive (HR+)/HER2– MBC. However, current literature has little data on real-world treatment patterns and health care resource use, particularly among elderly women with HR+/HER2– MBC in the United States Medicare population.
Methods
A retrospective analysis of patients aged ≥66 years diagnosed with MBC during 2007 to 2011 was conducted using the SEER-Medicare database. Patients' HR and HER2 status was obtained from the SEER registry data. For patients with no HER2 data available, HER2− disease was determined based on the absence of HER2-targeted therapies within 12 months of diagnosis. Health care utilization and treatment patterns after MBC diagnosis were examined. Use of cancer-directed therapies, including chemotherapy (CT) and endocrine therapy (ET), were descriptively analyzed by line of therapy (LOT).
Results
A total of 3,622 women with HR+/HER2– MBC (mean [SD] age, 77 [7.3] years) were included. Over 90% of women received ≥1 cancer-directed treatment after MBC diagnosis, with ET being the most common (77%), followed by CT (50%), radiation (48%), and surgery (19%). Treatment with ET alone trended downward across LOTs, from 74% in the first LOT to 36% in the fourth LOT, with a corresponding increase in treatment with CT alone from 21% to 46% (Table 1). Among those receiving a second LOT, nearly 26% switched to CT in the second line after having received ET alone in the first line.
Table 1. Pharmaceutical treatment patterns by line of therapy among patients diagnosed with HR+/HER2– MBC (n = 3622)First-Line Second-Line Third-Line Fourth-Line N = 2,981 (82%)* N = 1,449 (40%)* N = 750 (21%)* N = 356 (10%)* n (%) n (%) n (%) n (%)ET Alone2215 (74)ET Alone973 (67)ET Alone381 (51)ET Alone127 (36)Anastrozole893 (40)Fulvestrant282 (29)Fulvestrant99 (26)Fulvestrant38 (30)Letrozole602 (27)Exemestane190 (20)Exemestane76 (20)Tamoxifen27 (21)Tamoxifen253 (11)Anastrozole162 (17)Tamoxifen71 (19)Exemestane25 (20)Fulvestrant243 (11)Tamoxifen152 (16)Anastrozole46 (12)Anastrozole13 (10)Exemestane156 (7)Letrozole107 (11)Letrozole38 (10)Exemestane-FulvestrantN/ACT Alone639 (21)CT Alone336 (23)CT Alone264 (35)CT Alone165 (46)Paclitaxel136 (21)Paclitaxel76 (23)Paclitaxel78 (30)Paclitaxel39 (24)Cyclophosphamide-Docetaxel72 (11)Gemcitabine57 (17)Gemcitabine46 (17)Gemcitabine32 (19)Cyclophosphamide-Doxorubicin → Taxane69 (11)Docetaxel28 (8)Vinorelbine31 (12)Vinorelbine21 (13)Carboplatin-Paclitaxel43 (7)Vinorelbine27 (8)Docetaxel22 (8)Doxorubicin17 (10)Docetaxel39 (6)Doxorubicin21 (6)Doxorubicin21 (8)DocetaxelN/AN/A = not available (in accordance with the SEER-Medicare data use agreement, data for categories with cell size less than 11 are suppressed). *Out of total 3,622 patients. Note: Percentages do not add up to 100% as only the top CT and ET regimens are listed.
Conclusions
ET was the most common first-line treatment for elderly women with HR+/HER2– MBC in this study period. However, as patients progressed from first to fourth LOT, the proportion of patients treated with ET decreased substantially.
Citation Format: Goyal RK, Carter GC, Nagar SN, Smyth EN, Price GL, Huang Y-J, Bromund JL, Li L, Schilder JM, Davis KL, Kaye JA. Treatment patterns and resource utilization among elderly Medicare patients with HR+/HER2– metastatic 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 P5-08-19.