Chemotherapy and Cardiotoxicity in Older Breast Cancer Patients: A Population-Based Study
Key result
Doxorubicin chemotherapy in older women with breast cancer was associated with a substantially increased risk of cardiomyopathy compared to no chemotherapy (HR 2.48; 95% CI 2.10-2.93).
Why the study?
Does doxorubicin increase the risk of cardiomyopathy, congestive heart failure, and heart disease in older women with stage I to III breast cancer?
Population
31,748 women aged >= 65 years diagnosed with stage I to III breast cancer from January 1, 1992 to December…
Comparison
Chemotherapy, specifically doxorubicin vs No chemotherapy
Design
Cohort
Follow-up
long-term (at least 5 years)
Authors
Discussion
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Implication
Supports cardiac monitoring in older women on doxorubicin; hypothesis-generating for mitigation strategies pending randomized data.
Key Points
- To assess the acute and chronic cardiac toxicities associated with chemotherapy, particularly anthracyclines, in older women treated for breast cancer.
- Analyzed records from the SEER-Medicare database for 31,748 women aged ≥ 65 years diagnosed with stage I to III breast cancer between 1992 and 1999.
- Applied propensity scores to balance baseline heart disease and other chemotherapy predictors, using Cox proportional hazards models to evaluate risks of cardiomyopathy, congestive heart failure, and overall heart disease.
- Chemotherapy was administered to 5,575 of 31,748 patients (18%), with chemotherapy recipients less frequently presenting with pre-existing heart disease (45% vs 55%; P < .001).
- Compared with no chemotherapy, doxorubicin significantly increased the risk of cardiomyopathy (HR 2.48; 95% CI, 2.10 to 2.93), congestive heart failure (HR 1.38; 95% CI, 1.25 to 1.52), and heart disease (HR 1.35; 95% CI, 1.26 to 1.44).
- The elevated relative risk of cardiotoxicity among patients treated with doxorubicin persisted at 5 years following cancer diagnosis.
Study Design
Type
Cohort (n=31,748)
Multicenter
Yes
Structured PICO
Does doxorubicin increase the risk of cardiomyopathy, congestive heart failure, and heart disease in older women with stage I to III breast cancer?
P
Population
31,748 women aged >= 65 years diagnosed with stage I to III breast cancer from January 1, 1992 to December 31, 1999 (SEER-Medicare database).
I
Intervention
Chemotherapy, specifically doxorubicin (anthracyclines)
C
Comparator
No chemotherapy
O
Outcome
Risk of cardiomyopathy (CM), congestive heart failure (CHF), and heart disease (HD)safety
Main Result
Effect estimate: HR 2.48 (95% CI 2.10-2.93)
In older women with breast cancer, adjuvant chemotherapy with doxorubicin is associated with a significantly increased risk of cardiomyopathy and congestive heart failure compared to no chemotherapy.
Cite This Study
Doyle et al. (2005) conducted a cohort in stage I to III breast cancer (n=31,748). Doxorubicin (DOX) chemotherapy vs. No chemotherapy was evaluated on Cardiomyopathy (CM) (HR 2.48, 95% CI 2.10-2.93). Doxorubicin chemotherapy in older women with breast cancer was associated with a substantially increased risk of cardiomyopathy compared to no chemotherapy (HR 2.48; 95% CI 2.10-2.93).