Risk of Cardiovascular Diseases among Older Breast Cancer Survivors

SUMMARY: Breast cancer is the most common cancer among women in the US and about 1 in 8 women (12%) will develop invasive breast cancer during their lifetime. Approximately 284,200 new cases of breast cancer will be diagnosed in 2021 and about 44,130 individuals will die of the disease, largely due to metastatic recurrence.

Significant progress in breast cancer screening techniques, as well as new and novel therapies, have resulted in early cancer detection and improvement in the breast cancer 5-year survival rate in the US from 75% in the 1970s to 91% in the 2010s. Cardiovascular Disease (CVD) is the most frequent cause of noncancer-related death, and cardiotoxicities associated with cancer treatments may increase cardiovascular risk in this population of breast cancer survivors. However, few studies have in detail quantified the risks of the different clinically important cardiovascular outcomes. The authors therefore assessed the prevalence of the different clinically specific cardiovascular outcomes at breast cancer diagnosis, and their incidence after diagnosis, among survivors 65 years or older in the US, and compared this with similar women without cancer.

The researchers performed a matched cohort study using prospectively collected data from the SEER-Medicare linked claims-based database and identified all women older than 65 years of age with an incident Stage I-III breast cancer diagnosis in 2004 through 2013. Each patient with breast cancer was matched at diagnosis with 5 cancer-free female counterparts. Baseline prevalence of specific cardiovascular outcomes was measured, and the risk for individual cardiovascular outcomes during follow up was calculated, taking into consideration time since diagnosis, race/ethnicity, prior Cardiovascular Disease (CVD), and age. This study included a total of 91,473 women with breast cancer and 454,197 without breast cancer.

It was noted that women with breast cancer had lower baseline prevalence of all CVDs. Breast cancer survivors had substantially increased risks of Deep Vein Thrombosis and pericarditis, compared with cancer-free female counterparts. There was also evidence of smaller increased risks of sudden cardiac arrest, arrhythmia, heart failure, and valvular heart disease. The increased risks of arrhythmia, heart failure, pericarditis, and Deep Vein Thrombosis were most pronounced in the first year and persisted for more than 5 years after cancer diagnosis. There was evidence of a decreased risk of incident angina, myocardial infarction, revascularization, peripheral vascular disease, and stroke in breast cancer survivors, although this was not constant over time.

The CVD risk during follow up was consistently higher in African American women diagnosed with breast cancer compared with Caucasian women, regardless of whether there was an overall increased or decreased risk of outcomes during the entire follow up period, and this is consistent with racial differences in overall CVD risk in the US.

Finally, there was consistently a greater risk of all cardiovascular outcomes in those diagnosed with Stage III, Grade 3, and ER/PR-negative breast cancer, which may be a reflection of the more aggressive cancer treatment regimens used in these subtypes.

The authors concluded that there is evidence of increased risk of several cardiovascular diseases in elderly women diagnosed with breast cancer in the US, compared with similar women without cancer, with this risk persisting for several years after diagnosis. They added that these results highlight the importance of periodic cardiovascular evaluation throughout the long term follow up of women diagnosed with breast cancer.

Risk of Cardiovascular Diseases Among Older Breast Cancer Survivors in the United States: A Matched Cohort Study. Matthews AA, Hinton SP, Stanway S, et al. J Natl Compr Canc Netw 2021;19:275-284.