Left-sided breast cancer tumors were not associated with a higher risk of cardiac-related mortality compared to right-sided tumors following postoperative radiotherapy (HR 1.025; 95% CI 0.856-1.099).
Cohort (n=168,761)
Yes
Does left-sided tumor laterality increase cardiac-related mortality in breast cancer patients after radiotherapy compared to right-sided tumors?
In a large population-based cohort, left-sided breast cancer was not associated with increased cardiac-related mortality compared to right-sided breast cancer following modern radiotherapy.
Effect estimate: HR 1.025 (95% CI 0.856-1.099)
Absolute Event Rate: 2.3% vs 2.3%
p-value: p=0.484
Introduction: To assess the effect of tumor laterality to cardiac-related deaths of breast cancer in the current radiation practices using a large modern population-based study. Methods: Women diagnosed with breast cancer from 2000 to 2008 were included using the current Surveillance, Epidemiology, and End Results database. The primary outcome of this study was the cardiac-related mortality. Multivariate analysis was performed using the Cox proportional hazards model to analyze the cardiac-related mortality including demographic, clinicopathologic, and treatment factors. Results: We identified 168,761 breast cancer patients, including 85,006 (50.4%) patients with left-sided tumors and 83,755 (49.6%) patients with right-sided tumors. The median follow-up period was 8.8 years. The 10-year cardiac-related mortality was 2.3% and 2.3% in left- and right-sided tumors, respectively ( P =0.685). The results indicated that patients with older age, non-Hispanic Black, receipt of mastectomy, and married status were the independent adverse factors for cardiac-related mortality. However, left-sided tumors were not associated to a higher risk of cardiac-related mortality than right-sided tumors following postoperative radiotherapy (right vs left, hazard ratios 1.025, 95% CI 0.856–1.099, P =0.484). The risk of cardiac-related mortality in the entire cohort was increased with the extension of follow-up time. However, there was still not significantly different between left- and right-sided tumors. Subgroup analysis also found no association between tumor laterality and cardiac-related mortality after postoperative radiotherapy based on various demographics and treatment factors. Conclusion: With a median follow-up of 8.8 years, no significant differences were found in cardiac-related mortality between left- and right-sided tumors under current radiation practices of breast cancer patients. Keywords: breast cancer, radiotherapy, tumor laterality, cardiac mortality
Li et al. (Sat,) conducted a cohort in Breast cancer (n=168,761). Left-sided tumor (postoperative radiotherapy) vs. Right-sided tumor (postoperative radiotherapy) was evaluated on Cardiac-related mortality (HR 1.025, 95% CI 0.856-1.099, p=0.484). Left-sided breast cancer tumors were not associated with a higher risk of cardiac-related mortality compared to right-sided tumors following postoperative radiotherapy (HR 1.025; 95% CI 0.856-1.099).