Original StudyTreatment Patterns and Outcomes of Patients With Metastatic ER+/HER-2− Breast Cancer: A Multicountry Retrospective Medical Record Review
Introduction
In 2012, approximately 1.67 million women were diagnosed with breast cancer worldwide, and nearly 522,000 deaths were recorded.1 The age-standardized incidence of breast cancer is greater in developed regions than less developed regions, with the highest rates in North America (91.6 per 100,000) and Western Europe (89.4 per 100,000 persons). In Europe and Canada, 3-year survival among patients diagnosed with stage IV breast cancer ranges from 27.9% to 41.8%.2
Metastatic breast cancer is incurable; however, the presence or absence of hormone and epidermal growth factor receptors in breast tumors can inform the selection of therapies associated with optimal outcomes and quality of life.3 Approximately 70% of invasive breast cancers are hormone receptor positive (eg, estrogen receptor positive [ER+]), which typically respond well to endocrine therapy.4 In the metastatic setting, hormone receptor–positive and human epidermal growth factor receptor 2–negative (HER-2−) tumor status have a favorable prognosis over other subtypes.5 Across Europe, approximately 67% of patients with breast cancer are both hormone receptor positive and HER-2−.6
For postmenopausal women with locally advanced or metastatic ER+/HER-2− breast cancer, endocrine therapy is typically recommended, usually consisting of an aromatase inhibitor, a selective estrogen-receptor modulator, a selective estrogen-receptor down-regulator, or a progestin.3, 7 Clinical trials have reported median progression-free survival after initiation of first-line endocrine therapy ranging from 5.6 months while receiving tamoxifen8 to 15.0 months while receiving an anastrozole and fulvestrant combination regimen.9
Although endocrine therapy is the most effective treatment available, de novo resistance and resistance acquired during treatment can be a substantial barrier in managing metastatic breast cancer.10 Chemotherapy is recommended for patients with clear evidence of endocrine resistance as well as for those with extensive or symptomatic visceral involvement.3 However, chemotherapy is associated with toxicities and adverse effects that can negatively affect functional status and quality of life.7
Recent advancements in novel targeted therapies for hormone receptor–positive breast cancer have shown improvements in progression-free survival compared to the use of endocrine therapy alone.11 With the emergence of new treatments for ER+/HER-2− breast cancer, such as CKD4/6 and mammalian target of rapamycin (mTOR) inhibitors, substantial changes in breast cancer treatment options are occurring.11 Therefore, recent evaluations of current endocrine and chemotherapy treatment patterns and factors associated with disease progression and survival among patients with metastatic ER+/HER-2− breast cancer are needed. Further, research identifying patient populations with continued need for effective and safe treatments is essential, as patients who have poor prognosis under the current standard of care may benefit from novel therapies.
Section snippets
Study Design and Data Collection
This study was a retrospective medical record review of postmenopausal patients with metastatic ER+/HER-2− breast cancer. Physicians were recruited in Canada, the United Kingdom, Belgium, the Netherlands, Germany, Spain, and France to abstract data from the medical records of patients who were treated for metastatic ER+/HER-2− breast cancer. Physicians were eligible to participate as abstractors in the study if they were a practicing medical or clinical oncologist, oncologist hematologist, or
Physician Characteristics
A total of 258 physicians participated in the data abstraction. Most physicians were medical or clinical oncologists (76.36%). The mean (standard deviation [SD]) past-year metastatic ER+/HER-2− breast cancer postmenopausal case load among these physicians was 69.98 (58.03) patients. Mean (SD) number of years treating patients with postmenopausal metastatic breast cancer was 13.4 (5.8) years.
Patient Characteristics
Data from a total of 901 patients were analyzed (Table 1). Mean (SD) age at diagnosis of metastatic
Discussion
In the present study, nearly two-thirds of patients received first-line endocrine therapy, while the remaining patients received chemotherapy. This proportion also varied by country, ranging from 21% in Belgium and the Netherlands to 41% in France. Given the known safety and effectiveness of endocrine therapy, the observed proportion of patients who received chemotherapy was considerable. Treatment guidelines indicated chemotherapy should be considered among patients with visceral crisis.3
Conclusion
This study provides a current review of real-world treatment patterns, disease progression, and survival in a multinational population of patients with metastatic ER+/HER-2− breast cancer. Disease progression after first- and second-line endocrine and chemotherapy treatments is less than a year. Patients who were prescribed endocrine therapy in the first- or second-line setting had substantially longer TTP and OS compared to those who were prescribed chemotherapy. Patients who received
Disclosure
D.M. and G.Z. are employees of Pfizer Inc. S.K. and J.A.K. are employees of RTI Health Solutions, who were paid contractors to Pfizer Inc in the development of this article. This study was conducted by RTI Health Solutions under the direction of Pfizer Inc.
Acknowledgments
Editorial and graphics assistance was provided by Kelsey Tsipis, Laurel Trantham, and Jason Mathes of RTI Health Solutions, and was funded by Pfizer Inc. Project management support was provided by Christina Levine of RTI Health Solutions. Recruitment and data collection activities were conducted by A+A Research.
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