Abstract P4-13-14: “Real world” characteristics, treatment patterns and outcomes of patients with hormone receptor positive (HR+), human epidermal growth factor 2 negative (HER2-) metastatic breast cancer (MBC)

OBJECTIVES: Outcomes for patients with MBC vary according to disease phenotype and treatment history. We present UK real-world patient characteristics, treatment patterns and outcomes for patients with HR+/HER2- BC treated at a single cancer center.

METHODS: A retrospective review of health records including coded data, unstructured text and clinical review of patients treated from January 2012 to March 2018 identified females ≥ 18 years with metastatic or locally advanced HR+/HER2- BC. Those enrolled in clinical trials, with operable local recurrence as only disease site, incomplete treatment records or significant secondary malignancy were excluded. Patient characteristics, systemic, local (radiotherapy/surgery) and supportive treatments, health care resource use (HRU) and overall survival (OS) are presented. OS was estimated using the Kaplan-Meier method, censoring patients alive at study end.

RESULTS: 253 patients meeting study inclusion criteria were identified (median age 67, IQR 56,76; 84% post-menopausal), of whom 47 (19%) had locally advanced disease (T4 and/or N3), 75 (30%) had MBC at initial presentation and 131 (52%) had metastatic disease at first recurrence. Among patients with MBC at initial presentation, all received systemic treatment following diagnosis, including chemotherapy (35%), endocrine (93%) and targeted therapy (i.e. everolimus 7%). Among those recurring with MBC, 97% subsequently received systemic treatment, including chemotherapy (50%), endocrine (93%) and targeted therapy (27%). For patients recurring with MBC, the most common first line therapies (LoT) were letrozole (20%), exemestane (single agent, 15%), anastrozole (14%), everolimus (with exemestane, 11%) and paclitaxel (9%). For patients diagnosed with MBC, the most common first LoT were letrozole (47%), anastrozole (23%) and EC (11%). At second LoT, the most commonly used regimen for patients recurring with MBC was fulvestrant (13%) and for patients with MBC at initial diagnosis, it was exemestane (19%). Median OS for patients recurring with MBC was estimated to be 2.11 years (IQR 1.80,3.05), compared with 2.65 years (IQR 2.24,2.95) for those with metastatic disease at initial diagnosis. Median available follow-up time for the whole cohort was 2.85 years (IQR 1.42,4.82).

CONCLUSIONS: Patients with overt metastatic disease at presentation comprise a substantial proportion of those treated for MBC. With the follow-up time available, estimated median OS for patients with metastatic disease at initial presentation appears somewhat better than for those recurring with metastatic disease. Real world analysis demonstrates diverse treatment pathways for patients with HR+, HER2- MBC, reflecting the individualized care they receive.

Citation Format: Twelves C, Cheeseman S, Thompson M, Riaz M, Perren T, Ahat-Donker N, Sopwith W, Myland M, Lee A, Turner S, Hall G. “Real world” characteristics, treatment patterns and outcomes of patients with hormone receptor positive (HR+), human epidermal growth factor 2 negative (HER2-) metastatic breast cancer (MBC) [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-13-14.