Abstract PS1-09-14: Evaluating clinical and molecular correlates of Inflammatory Breast Cancer using a scoring system-based chart review

Abstract Background: Inflammatory breast cancer (IBC) is a rare and aggressive form of breast cancer with a distinct clinical presentation and poor prognosis. Diagnostic ambiguity remains a challenge, and recent literature has proposed structured criteria to improve case classification. Methods: We conducted a retrospective chart review of 83 patients diagnosed with IBC and 83 patients with non-inflammatory breast cancer (non-IBC), seen at the University of Texas Southwestern Medical Center as part of the Dallas Metastatic Cancer Study. Each IBC case was evaluated using a structured scoring system adapted from the diagnostic guidelines proposed by Omarini et al. (2022) to assess the degree of conformity to established IBC features. Clinical and pathological characteristics were compared across groups using appropriate statistical tests. Results: Our findings reinforce several established associations in the literature. Compared to non-IBC patients, those with IBC exhibited significantly higher Ki-67 proliferation indices (1.42-fold increase, p<0.0001, Mann-Whitney U test), greater number of metastatic sites (2-fold increase, p<0.0001, Mann-Whitney U test), and higher clinical stage at diagnosis (p = 0.04, Chi-square test). IBC cases were also associated with more aggressive disease biology as they were more likely to be ER negative (p = 0.003, Fisher test) and PR negative (p = 0.0184, Fisher test). Notably, we observed a novel pattern: IBC was significantly associated with specific metastatic sites, particularly the brain (4.5 times more likely in IBC patients, p<0.0001, Chi-square test) and lungs (2.08 times more likely in IBC, p = 0.0028, Chi-square test), suggesting a potentially distinct metastatic tropism. Conclusions: This study supports the diagnostic utility of a structured scoring system for IBC and confirms key clinical and molecular trends observed in prior research. The novel association with specific metastatic sites warrants further investigation and may inform future efforts in IBC classification and management. Citation Format: C. M. Atallah, A. Varner, C. J. Kang, P. Gowda, K. Anderson, D. Tovar, R. Morey, C. Hauer, R. Sridharan, S. Huang, K. Lei, S. M. Reddy, H. L. McArthur, J. Maués, C. Hodgdon, B. Zhang, X. Zhang, B. Lim, I. S. Chan. Evaluating clinical and molecular correlates of Inflammatory Breast Cancer using a scoring system-based chart review [abstract]. In: Proceedings of the San Antonio Breast Cancer Symposium 2025; 2025 Dec 9-12; San Antonio, TX. Philadelphia (PA): AACR; Clin Cancer Res 2026;32(4 Suppl):Abstract nr PS1-09-14.