ATYPICAL RESPONDERS LANDSCAPE REVIEW ∙ OCTOBER, 2017 2 Abstract 3 Introduction 5 Research and Analysis 7 Initiatives that are Investigating an “Atypical Response” and Associated Descriptions 7 Benefits of Studying Atypical Responses 14 Factors Contributing to Atypical Responses 16 Exceptional Survivors 27 Challenges and Future Directions 28 Suggested Action Items for the MBCA, Other Advocacy Organizations, and Researchers 29 Summary 30 Tables 31 Table 1: Categories and Terms Related to Atypical Responders 31 Table 2: Current Initiatives Studying Atypical Responses 33 Table 3: Summary of Published Studies Examining Atypical Responses 34 Table 4: Framework for Three Categories of Atypical Responders 35 Figure 1: Overview of Atypical Response Analyses and Related Clinical Outcomes 36 Glossary of Terms (in bold text) 37 References 42 Note: An abbreviated version of this work was published in NPJ Breast Cancer (De La Torre K, et al., NPJ Breast Cancer 2017 Mar 16;3:7 doi 10.1038/s41523-017-0010-1) TABLE OF CONTENTS