No association between tumor laterality and cardiac-related mortality in breast cancer patients after radiotherapy: a population-based study

Abstract

IntroductionTo 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.MethodsWomen 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.ResultsWe 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.ConclusionWith 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.

A nested case-control study on radiation dose-response for cardiac events in breast cancer patients in Germany

“…Our findings are generally supported by recent studies that used tumor laterality as a surrogate measure, showing no significantly increased risk for cardiac late effects for more recent treatment periods including 1998–2008 [ 19 ], 1999–2006 [ 28 ], 2000–2008 [ 29 ], 2000–2009 [ 30 ], 2001–2005 [ 31 ]. In addition, our results are in line with two recently published large clinical trials with long-term follow-up [ 32 , 33 ].…”

The impact of tumor characteristics on cardiovascular disease death in breast cancer patients with CT or RT: a population-based study

“…The effect of tumour laterality on the risk of CVD death in breast cancer with RT remains controversial. Similarly, numerous studies indicated no excess of cardiac diseases and mortality among breast patients received left-sided radiotherapy compared with the right-sided group (49)(50)(51). Our study did not observe a statistically significant association of tumor laterality with CVD death.…”

Long-Term Risk of Death From Heart Disease Among Breast Cancer Patients

“…The risk of death from heart disease after radiotherapy is suspected to be higher in patients with left-sided disease as these patients typically receive on average higher radiation doses to the heart compared to patients with right-sided disease ( 10 , 17 , 19 ). Li et al, shows that there is no statistically significant difference between disease laterality and risk of cardiac-related mortality, as the HRs for right vs. left-sided tumor is 1.025 (95% CI 0.856–1.099, p = 0.484) ( 20 ). Our analysis similarly does not observe a statistically significant difference for cardiac mortality on the basis of disease laterality, shown in Figures 1B,C , 3 .…”