Abstract P6-15-03: Inflammatory breast cancer (IBC) defined: Proposed common diagnostic criteria and scoring - Moving beyond the subjective ‘clinical diagnosis’ of IBC to advance research

Spurred by the lack of progress in improving outcomes in patients with inflammatory breast cancer (IBC), a deadly and aggressive type of breast cancer, Susan G. Komen, the Inflammatory Breast Cancer Research Foundation, and the Milburn Foundation convened patient advocates, breast cancer researchers, and clinicians to review the state of IBC care and research globally, and propose specific initiatives to move the field forward. The outcome of the discussions was abundantly clear: the field needs a formal definition of IBC. Without a clear definition, both patient care and research suffer. Diagnosis remains subjective and treatment variable. Clinical trials become inherently underpowered by inclusion of subjects with locally advanced, but not inflammatory, breast cancer. Similarly, the search for a molecular sine qua non or unifying pathway aberration is hindered by inclusion of bio-specimens from subjects with a different disease. The goal is to move beyond the subjective ‘clinical diagnosis’ to a set of specific diagnostic criteria and scoring system that will advance IBC research and facilitate the discoveries that will improve care of IBC patients. Here we propose a definition of IBC, based on a review of clinical, and pathologic features. With increased awareness of IBC, patients are coming to medical attention earlier when clinical characteristics may not be as profound as historically depicted. Not all criterion are required for a diagnosis. To determine the total score, multiply the priority factor by the score for each criteria, then add the subtotals for each criteria. A priority factor is used to weigh criterion more heavily that are key to a consistent diagnosis of IBC to better define breast cancers that are ambiguous. While we cannot currently recommend a molecular-genetic profile that unambiguously identifies IBC, we will also provide a panel of prioritized biomarkers that are strongly associated with IBC and deserve further study in cohorts meeting our diagnostic criteria. We acknowledge that our proposed scoring system requires validation and refinement. If accurate, we expect patients with IBC based on these criteria to have a different clinical course and outcome compared to patients with “non-inflammatory” locally advanced breast cancer (LABC). Ultimately, we envision using the final disease classification and scoring system to develop a staging system specific to IBC. The discovery and validation of a distinct molecular or genetic profile that identifies IBC is of utmost importance to advancing research in this disease and cannot be accomplished without a clear and validated definition of IBC. Citation Format: Ginny Mason, Beth A Overmoyer, Wendy A. Woodward, Sunil Badve, Robert J. Schneider, Reshma Jagsi, Julie E. Lang, Mary Alpaugh, Krissa Smith, Kathy Miller. Inflammatory breast cancer (IBC) defined: Proposed common diagnostic criteria and scoring - Moving beyond the subjective ‘clinical diagnosis’ of IBC to advance research [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P6-15-03.