Abstract P1-07-22: Infectious disease hospitalization in breast cancer patients: Risk and impact on prognosis

Abstract

Abstract Background: Infection-related hospitalizations are a serious complication in breast cancer patients, resulting in treatment delay, prolonged hospitalization and future morbidity and mortality. Little, however, is known about the actual risk, clinical characteristics and outcomes of infection-related hospitalizations in this patient population. Methods: We conducted a prospective population-based study including 7071 women diagnosed with primary invasive non-metastatic breast cancer between 2001 and 2008 in the Stockholm-Gotland region (Sweden), with complete follow-up until 2010. Standardized incidence ratios (SIRs) for infection-related hospitalizations (overall and by site) were estimated using background rates from the general female population, matched on age and calendar period. Associations with clinical characteristics and breast cancer outcomes (breast cancer death, distant metastasis and locoregional recurrence) were analysed using flexible parametric survival models. Results: During a medium follow-up of 5.3 years, 657 hospital admissions with infections were observed and 1,2 and 5-year cumulative risks were 3.4, 4.7 and 8.1% respectively. Rates of infection-related hospitalizations were increased compared to the general female population (SIR = 2.12; 95% CI = 1.96-2.29) and site-specific SIRs were most pronounced for sepsis (SIR = 3.65; 95% CI = 3.13-4.26) and skin infections (SIR = 2.93; 95% CI = 2.35-3.64). The overall risk of infections was highest during the first year (SIR = 5.06; 95% CI, 4.46-5.74), and recurrent disease contributed to the long-term risk observed. Older age at diagnosis, chemotherapy, axillary radiotherapy, comorbidities and markers of tumor aggressiveness (large tumors, estrogen receptor negative tumors and lymph node positive tumors) were independent predictors of infectious disease risk. Analyses evaluating the prognostic impact of infections revealed an independent effect on breast cancer death and distant metastasis, associations that were mainly driven by sepsis (HR = 4.53; 95% CI, 3.25-6.33 and 1.69; 95% CI, 1.04-2.79 respectively). No association was found with future risk of locoregional recurrence. Conclusions: Physicians and patients should be aware of the risk of serious infections which persists beyond the initial treatment period. Infection-related hospitalizations are an independent marker of poor prognosis. Further research is needed to elucidate the role of sepsis in breast cancer progression. Citation Format: Brand JS, Colzani E, Johansson A, Giesecke J, Clements M, Bergh J, Hall P, Czene K. Infectious disease hospitalization in breast cancer patients: Risk and impact on prognosis. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P1-07-22.