Abstract PS7-18: The impact of insurance status on survival in patients with inflammatory breast cancer (IBC) and non-IBC among a unique population in Hawaii
Authors: Miyazaki Kyle SY , Acoba Jared D , Fujii Takeo 
Published: February 2021

Background: Breast cancer is one of the most common types of cancer in United States women, with inflammatory breast cancer (IBC) being among the most aggressive, accounting for only 1-4% of all breast cancer cases yet causing 8-10% of breast cancer related deaths. It is reported that survival outcomes differ significantly between races and that specific races such as African-American tend to have aggressive and advanced disease. Previously, we reported that the proportion of IBC to non-IBC is significantly high in Native Hawaiian (NH) and Pacific Islander (PI) populations. The same study showed that NH and PI have shorter overall survival (OS) than Caucasians in patients with non-IBC but not in those with IBC. However, it is still not well known if poor prognosis in specifc races is due to aggressive disease biology, advanced stage at diagnosis, or socioeconomic status such as insurance status. Our primary objective was to determine the factors that predict OS after adjusting for baseline patient and disease characteristics. One of the novelties in our study is that we analyzed IBC and non-IBC, separately in our unique population in Hawaii. Methods: Patients with newly-diagnosed primary invasive breast cancer were identified from January 1, 2000 through December 31, 2018 using The Queen’s Medical Center Tumor Registry in Honolulu, Hawaii. Patients whose baseline and disease characterics were not available were excluded from the final analysis. Clinical T4d was used to differentiate IBC and non-IBC. OS was defined as the time from diagnosis to death or last follow-up. Patients who were alive at the date of last follow-up were censored. All the variables were summarized using standard descriptive statics. Univariate and multivariate cox proportional hazards models were used to assess the effects of variables of interest on OS. P-values &lt;0.05 were considered statistically significant. Results: A total of 1,442 patients were included in the final analysis. There were 44 patients with IBC. The proportions of IBC to non-IBC were significantly high in NH and PI (P=0.005, respectively), which is consistent with our previous report. In multivariate cox regression proportional hazards model adjusted for all variables that were significant in the univariate analysis, NH or PI were not significant predictive factors of OS in both IBC and non-IBC (IBC: Native Hawaiian HR 1.23, [95%CI, 0.2-7.4], P=0.82, Pacific Islander HR 1.51, [95%CI, 0.12-18.5], P=0.75; non-IBC: Native Hawaiian HR 0.75, [95%CI, 0.34-1.64], P=0.47, Pacific Islander HR 1.35, [95%CI, 0.55-3.33], P=0.52). Medicaid and no insurance were significantly associated with short OS in both IBC and non-IBC (IBC: Medicaid: HR 6.39, [95%CI, 1.21-33.9], P=0.03, No Insurance: HR 14.7, [95%CI, 1.7-127], P=0.02; non-IBC: Medicaid: HR 2.45, [95%CI, 1.12-5.34], P=0.02, No Insurance: HR 17.3, [95%CI, 3.31-89.8], P=0.001). Pacific Islanders were more often under or uninsured (P&lt;0.001). In addition, triple-negative breast cancer subtype and advanced stage were significantly associated with short OS in both IBC and non-IBC. Conclusions: This is the first study to investigate the association between patient, disease characteristics and socioeconomic status in a unique population focusing on Native Hawaiians and Pacific Islanders with IBC and non-IBC, separately. Insurance status was a significant prognostic factor after adjusting for patient and disease characteristics but race was not. Our result suggests that improving social determinants such as insurance support might improve the outcomes of patients with breast cancer including IBC, regardless of race.

Citation Format: Kyle SY Miyazaki, Jared D Acoba, Takeo Fujii. The impact of insurance status on survival in patients with inflammatory breast cancer (IBC) and non-IBC among a unique population in Hawaii [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS7-18.