Maastricht University Medical Center, The Netherlands
Scientific Tracks Abstracts: J Cancer Sci Ther
Background: Results in breast cancer research are reported using study endpoints. Most are composite endpoints (such as locoregional recurrence), consisting of several components (for example local recurrence) that are in turn composed of events (such as skin recurrence). Inconsistent endpoint selection and definition might lead to unjustified conclusions when comparing study outcomes. This study aimed to determine which locoregional endpoints are used in breast cancer studies, and how these endpoints and their components are defined. Methods: PubMed was searched for breast cancer studies published in nine leading journals in 2011. Articles using endpoints with a local or regional component were included and definitions were compared. Results: Twenty-three different endpoints with a local or regional component were extracted from 44 articles. Most frequently used were disease-free survival (25 articles), recurrence-free survival (7), local control (4), locoregional recurrence-free survival (3) and event-free survival (3). Different endpoints were used for similar outcomes. Five of 23 endpoints were not defined, 18 were defined partially. Of these, 16 contained a local and 13 a regional component. Included events were not specified in 33/57 (local) and 27/50 (regional) cases. Definitions of local components inconsistently included carcinoma in situ and skin and chest wall recurrences. Regional components inconsistently included specific nodal sites and skin and chest wall recurrences. Conclusion: Breast cancer studies use many different endpoints with a locoregional component. Definitions of endpoints and events are not always provided and may vary between studies. To improve transparency, facilitate comparison of results and avoid unjustified conclusions, authors should provide detailed definitions of endpoints.
Martine Moossdorff completed her medical degree with honors at Maastricht University in the Netherlands. In her final year of medical school, she joined the breast surgery research group. Supervised by Dr. Marjolein L. Smidt, she is currently a PhD candidate at Maastricht University. Her research is focused on consistent definitions of endpoints in breast cancer research, and the occurrence of local and regional recurrences.