Use Of Surveillance, Epidemiology, And End Results (SEER)-Medicare Data to Characterize the Demographics, Disease Characteristics, Comorbidities, And Survival of Elderly (≥65 Years) Patients with Human Epidermal Growth Factor Receptor-2-Positive Breast Cancer as Primary Cancer in the United States Volume 4 - Issue 5

Nora Tu¹*, Zahidul Islam¹, Mackenzie Henderson^1,2 and Maribel Salas^1,3

• ¹Global Epidemiology Department, Daiichi Sankyo, USA
• ²Rutgers Institute for Pharmaceutical Industry Fellowships, Rutgers University, USA
• ³Center for Clinical Epidemiology and Biostatistics (CCEB)/Center for Pharmacoepidemiology Research and Training (CPeRT), University of Pennsylvania Perelman School of Medicine, USA

Received:August 5, 2021   Published: August 19, 2021

Corresponding author: Nora Tu, Global Epidemiology Department, Daiichi Sankyo, 211 Mount Airy Road, Basking Ridge, NJ, USA

DOI: 10.32474/OAJOM.2021.04.000198

 

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Abstract

Purpose: A retrospective cohort analysis to investigate comorbidities and 5-year survival in elderly patients (≥65 years) with human epidermal growth factor receptor-2-positive (HER2-positive) breast cancer (BC) using data from the Surveillance, Epidemiology, and End Results (SEER)-Medicare program

Methods: Female patients aged ≥65 years with a HER2-positive BC diagnosis as the first cancer diagnosis (between 1/1/2010– 12/31/2015) were eligible. Comorbidities and 5-year survival of HER2-positive BC patients (irrespective of stage) were compared with age/race-matched non-cancer controls. Survival data (time-to-death) were unadjusted and adjusted by comorbidities and region.

Results: Data from 8978 HER2-positive BC patients and 8978 controls were included. Mean age was 77.1 years (range: 66.0– 102.8 years). Most cancers were Stage I (35.1%) or II (33.2%) at diagnosis. Thirteen/24 predefined comorbidities were significantly more prevalent in HER2-positive BC patients versus controls (P < 0.05). The most prevalent comorbidities in HER2-positive BC patients were anemia, hypertension, and arthritis. Generally, comorbidities were more likely to be diagnosed before HER2-positive BC diagnosis. The estimated probability of 5-year survival was 69.7% (95% CI: 68.6%, 70.7%) for BC patients compared to 82.4% (95% CI: 81.5%, 83.3%) for controls. The risk of dying was higher among HER2-positive BC patients compared to non-cancer controls, with an unadjusted hazard ratio (HR) of 1.843 (95% CI 1.734,1.960) and adjusted HR of 1.934 (95% CI 1.819,2.057).

Conclusions: Many comorbidities were more prevalent in elderly patients with HER2-positive BC compared with controls, though few were more prevalent in controls. Comorbidities were generally more likely to be diagnosed prior to HER2-positive BC diagnosis. Mortality risk in patients with HER2-positive BC was higher than controls even after adjusting by comorbidities, suggesting that other factors are involved in the survival of elderly patients with HER2-positive BC. The clinical relevance of comorbidities in HER2+ BC patients and controls requires further study.

Keywords: Comorbidity; Elderly; HER2-positive breast cancer; SEER-Medicare; Survival

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Abstract| Introduction| Materials and Methods| Statistical analysis| Results| Discussion| Conclusion| Data Availability| Compliance with Ethical Standards| Ethical approval| Informed Consent:| Acknowledgements| References|