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

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.