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Research Paper|Volume 14, Issue 3|pp 1186—1199

Breast cancer mortality as a function of age

Azadeh Nasrazadani1, Juan Luis Gomez Marti2, Kevin E. Kip3, Oscar C. Marroquin3, Lara Lemon3,4, Steve D. Shapiro5, Adam M. Brufsky1
  • 1Division of Medical Oncology, Department of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
  • 2Department of Pathology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA
  • 3Clinical Analytics, University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA
  • 4Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Pittsburgh Medical Center, Pittsburgh, PA 15213, USA
  • 5Keck Medicine of USC, University of Southern California, Los Angeles, CA 90007, USA
* Equal contribution
Received: November 4, 2021Accepted: January 28, 2022Published: February 8, 2022
https://doi.org/10.18632/aging.203881

Copyright: © 2022 Nasrazadani et al. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Abstract

Background: Incidence of breast cancer (BC) in US women continues to increase with age as the strongest risk factor. We aimed to compare clinical, pathological and sociological variables associated to BC diagnosis, as well as the relative mortality rates of BC patients compared to the general US population.

Methods: We performed a retrospective, single-institution study evaluating 52,509 patients diagnosed with unilateral BC at the University of Pittsburgh Medical Center (UPMC) between 1990–2020. Primary outcome was death from any cause with cancer recurrence as a secondary outcome, evaluated for 4 age groups: 20–44, 45–55, 56–69, and 70–90. A dataset of expected mortality for women in the general population over a 10-year period was constructed using the Surveillance, Epidemiology, and End Results (SEER) Program. Observed vs. expected mortality and standardized mortality ratios (SMR) for each age group were calculated.

Results: Youngest patients with BC demonstrated the highest SMR at 10-year follow-up from time of diagnosis compared to the general US population (SMR 9.68, 95% CI: 8.99to 10.42), and remained highest compared to other age groups when analysis was limited to Stage 0/1 disease (10-year SMR 3.11, 95% CI: 2.54 to 3.76). SMRs decreased with increasing age at diagnosis with an SMR <1.0 in patients diagnosed with stage 0/1 at ages 70–90 at 5-year follow-up.

Conclusions: Younger BC patients have the highest SMR which declines gradually with age. In the elderly, lower stage 0/1 SMR’s are found compared to the general population, suggesting the possibility of an associated protective effect.