Disparities with influenza vaccine use in long-term survivors of metastatic breast cancer

Abstract

Purpose: Elderly women diagnosed with metastatic breast cancer (MBC) are living longer, however their primary care management may be sub-optimal. Influenza results in preventable hospitalizations and deaths. Guidelines recommend the influenza vaccine for those > 65 years and those with cancer but use is unknown.

Methods: A retrospective analysis was conducted using the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked data. Patients were included if they were diagnosed with MBC from 1/1/2008-12/31/2017 and were ≥ 65 years of age. The primary outcome was influenza vaccine use among patients surviving ≥ 3-years. We conducted multivariable analyses using demographic and clinical factors to identify associations with vaccine use. We compared utilization to cancer-free controls.

Results: We identified 1,970 patients with MBC that survived for ≥ 3 years. The median age at diagnosis was 73 years. Furthermore, 1,742 (88%) patients were White, and 153 (8%) patients were Black. Only 1,264 (64%) received an influenza vaccine at least one time and 51% received the vaccine at least two times. A multivariable model found lower odds of vaccine receipt for Black patients (OR = 0.48; 95% CI 0.34-0.68, p < 0.001) and higher odds for patients that saw primary care in the year prior to diagnosis (OR = 1.91, 95% CI 1.57-2.33, p < 0.001). Patients with MBC had lower odds of vaccine use compared to cancer free controls (OR = 0.85, 95% CI 0.74-0.97, p < 0.001).

Conclusion: Over 1/3 of long-term MBC survivors in our cohort did not receive the influenza vaccine. Black patients are about half as likely to be vaccinated. Given the known benefit of the vaccine, improving uptake could be an important strategy to improve outcomes.

Keywords: Influenza vaccine; Metastatic breast cancer; Primary care; SEER-Medicare; Survivorship.