Factors associated with early death from de novo metastatic breast cancer in Ontario, Canada.
Abstract
Background
Early death from female breast cancer is influenced by disease biology and factors such as age, marginalization, socioeconomic status, rurality, and access to primary care. Our objective was to investigate factors associated with early death in the subgroup of patients diagnosed with advanced de novo metastatic breast cancer, defined by the presence of distant metastatic disease at initial presentation.Methods
We used linked health care administrative data from Ontario, Canada, from 2010 to 2019 to conduct a population-based retrospective cohort study. We identified adults diagnosed with de novo metastatic breast cancer through the Ontario Cancer Registry. The primary outcome was the frequency of early death, defined as death within 6 months of cancer diagnosis. We used a multivariable logistic regression model to determine the patient, cancer, and provider characteristics associated with early death.Results
Among 4004 patients diagnosed with de novo metastatic breast cancer, 22.9% (n = 918) experienced early death. A higher Ontario Marginalization Index score for the domains of households and dwellings, and material resources was significantly associated with early death (odds ratio [OR] 1.27, 95% confidence interval [CI] 1.04 to 1.55, and OR 1.21, 95% CI 1.00 to 1.46, respectively). Registration with a primary care physician was associated with significantly decreased odds of early death (OR 0.74, 95% CI 0.62 to 0.88). We observed variability in early death across geographic regions and an increase in early death among patients living in rural areas after the start of systemic therapy.Interpretation
Marginalization, access to a primary care physician, and geography play a role in early death in patients diagnosed with de novo metastatic breast cancer in Ontario. Improving access to primary care providers may help reduce early death in these patients.
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BibTeX
@article{thomas2026factors,
title = {{Factors associated with early death from de novo metastatic breast cancer in Ontario, Canada.}},
author = {Priya Thomas and Brooke Carter and Craig C Earle and Salimah Z Shariff and Jacques Raphael and Alyson Mahar and Sarah Knowles and Muriel Brackstone and Michael Lock and Andrea Eisen and Areej Hezam and Phillip S Blanchette},
journal = {CMAJ : Canadian Medical Association journal = journal de l'Association medicale canadienne},
year = {2026},
month = oct,
doi = {10.1503/cmaj.260156},
url = {https://europepmc.org/article/MED/42896877},
note = {CC BY-NC-ND},
}
RIS
TY - JOUR
TI - Factors associated with early death from de novo metastatic breast cancer in Ontario, Canada.
AU - Priya Thomas
AU - Brooke Carter
AU - Craig C Earle
AU - Salimah Z Shariff
AU - Jacques Raphael
AU - Alyson Mahar
AU - Sarah Knowles
AU - Muriel Brackstone
AU - Michael Lock
AU - Andrea Eisen
AU - Areej Hezam
AU - Phillip S Blanchette
PY - 2026
DA - 2026/10/18
JO - CMAJ : Canadian Medical Association journal = journal de l'Association medicale canadienne
DO - 10.1503/cmaj.260156
UR - https://europepmc.org/article/MED/42896877
AB - Background Early death from female breast cancer is influenced by disease biology and factors such as age, marginalization, socioeconomic status, rurality, and access to primary care. Our objective was to investigate factors associated with early death in the subgroup of patients diagnosed with advanced de novo metastatic breast cancer, defined by the presence of distant metastatic disease at initial presentation.Methods We used linked health care administrative data from Ontario, Canada, from 2010 to 2019 to conduct a population-based retrospective cohort study. We identified adults diagnosed with de novo metastatic breast cancer through the Ontario Cancer Registry. The primary outcome was the frequency of early death, defined as death within 6 months of cancer diagnosis. We used a multivariable logistic regression model to determine the patient, cancer, and provider characteristics associated with early death.Results Among 4004 patients diagnosed with de novo metastatic breast cancer, 22.9% (n = 918) experienced early death. A higher Ontario Marginalization Index score for the domains of households and dwellings, and material resources was significantly associated with early death (odds ratio [OR] 1.27, 95% confidence interval [CI] 1.04 to 1.55, and OR 1.21, 95% CI 1.00 to 1.46, respectively). Registration with a primary care physician was associated with significantly decreased odds of early death (OR 0.74, 95% CI 0.62 to 0.88). We observed variability in early death across geographic regions and an increase in early death among patients living in rural areas after the start of systemic therapy.Interpretation Marginalization, access to a primary care physician, and geography play a role in early death in patients diagnosed with de novo metastatic breast cancer in Ontario. Improving access to primary care providers may help reduce early death in these patients.
SN - 0820-3946
SN - 1488-2329
ER -