What question did this study set out to answer?

The study aims to evaluate the relationship between physical activity and mortality in breast cancer survivors, considering menopausal status and competing risks.

April 5, 2026

Abstract 5032: Physical activity and overall and cancer-specific mortality in postmenopausal women with breast cancer: A competing risks analysis with 19-year follow-up

Key Result

Pre-diagnosis physical activity was associated with significantly lower overall and cancer-specific mortality in postmenopausal women with breast cancer over a 19-year follow-up.

Key Points

The study aims to evaluate the relationship between physical activity and mortality in breast cancer survivors, considering menopausal status and competing risks.
Analyzed 1000 breast cancer cases from the CAMA study over a 19-year follow-up.
Dichotomized leisure-time moderate-to-vigorous physical activity at 2.5 hours/week.
Employed Cox and Fine-Gray competing risks models to assess mortality outcomes.
Adjusted models for clinical, lifestyle, and socioeconomic confounders.
Handled missing data with Multiple Imputation by Chained Equations using Random Forest.
Menopausal status significantly influenced the relationship between physical activity and overall mortality (p=0.035).
In postmenopausal women, increased physical activity was linked to lower overall mortality.
No significant association between physical activity and mortality was found in premenopausal women.
Physical activity was associated with reduced cancer-specific mortality when considering non-cancer mortality.

Structured PICO

Does moderate-to-vigorous physical activity before diagnosis reduce overall and cancer-specific mortality in women with breast cancer?

Population

1000 breast cancer cases from the multicenter CAMA study in Mexico, including a subgroup of 584 postmenopausal women

Intervention

Leisure-time moderate-to-vigorous physical activity ≥2.5 h/week before breast cancer diagnosis or symptoms

Comparator

Leisure-time moderate-to-vigorous physical activity <2.5 h/week before breast cancer diagnosis or symptoms

Outcome

Overall, cancer, and non-cancer mortalityhard clinical

In postmenopausal women with breast cancer, moderate-to-vigorous physical activity before diagnosis is associated with lower overall and cancer-specific mortality over a 19-year follow-up.

Main Result

Absolute Event Rate: 0% vs 0%

Abstract

Abstract Background: As breast cancer survivors live longer, non-cancer mortality competes with cancer mortality. However, many studies evaluating physical activity have not accounted for competing risks or adequately tested effect modification by menopausal status. Therefore, we aimed to assess the association between physical activity and mortality in women with breast cancer, accounting for menopausal status and competing risks. Methods: We analyzed 1000 breast cancer cases from the multicenter CAMA study in Mexico with 19-year follow-up. Usual hours of leisure-time moderate-to-vigorous physical activity before breast cancer diagnosis or symptoms were dichotomized at 2.5 h/week. Primary outcomes were overall, cancer, and non-cancer mortality. We used a two-stage analysis: (1) Cox model for overall mortality testing menopausal status as an effect modifier, and (2) Fine-Gray competing risks models in strata with significant effects. Models were adjusted for DAG-derived clinical, lifestyle, and socioeconomic confounders. Missing data were handled using Multiple Imputation by Chained Equations with Random Forest. Results: Menopausal status significantly modified the association between physical activity and overall mortality (p=0.035). In postmenopausal women (n=584), physical activity was associated with reduced mortality (Table), with no significant association in premenopausal women. Conclusions: In postmenopausal women with breast cancer, physical activity before diagnosis or symptoms was associated with lower overall mortality at long-term follow-up. This benefit reflects significantly lower cancer-specific mortality when accounting for competing non-cancer mortality. These findings underscore the importance of physical activity after menopause and highlight the need for methodological approaches that jointly consider menopausal status and competing risks in survivorship research. Citation Format: Jaime I. Castillo Silva, Lina S. Palacio Mejia, Juan E. Hernandez Avila, Salvador Zamora Muñoz, Rocío Rodriguez Valentin, Angélica Angeles Llerenas, Amado Jiménez Avila, Gabriela Torres Mejía. Physical activity and overall and cancer-specific mortality in postmenopausal women with breast cancer: A competing risks analysis with 19-year follow-up abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2026; Part 1 (Regular Abstracts); 2026 Apr 17-22; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2026;86(7 Suppl):Abstract nr 5032.

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