Screening and treatment advances have led to substantial improvements in breast cancer survival rates in recent years, with roughly 90% of patients now surviving 5 years beyond diagnosis.1
However, higher rates of death due to cardiovascular disease (CVD) have been observed in this population compared with the general population. In fact, researchers have found that CVD accounts for 35% of deaths unrelated to cancer in breast cancer survivors older than 50 years.2
“As the leading cause of death among women in the United States, CVD represents a major public health issue for all women, but it is of particular concern for those with a history of breast cancer,” said Jennifer Yeong-Shin Sheng, MD, assistant professor of oncology at Johns Hopkins University School of Medicine in Baltimore.
“The risk of CVD mortality increases significantly after a diagnosis of breast cancer, and CVD represents a top cause [of death] in these patients,” she added.
A 2011 study suggested that CVD was the leading cause of death among patients with breast cancer.3 The study included 63,566 patients followed for a median of 9 years.
A 2021 study indicated that CVD was the second leading cause of death among breast cancer survivors.4 In this study, Ramin et al examined all-cause and CVD-related mortality rates in 628 breast cancer survivors compared with 3140 age-matched cancer-free women over a period of 25 years.
Short-Term vs Long-Term Risk
Along with increased rates of all-cause mortality among breast cancer survivors (hazard ratio [HR], 1.79; 95% CI, 1.53-2.09), Ramin et al found that CVD mortality was significantly higher beginning at 8 years after breast cancer diagnosis (HR, 1.65; 95% CI, 1.00-2.73) but not in the first 8 years after diagnosis.4
In a 2016 study, Bradshaw et al reported a sharp increase in CVD-related mortality among breast cancer survivors after 7 years of follow-up.5 When compared with cancer-free women, breast cancer survivors had nearly twice the risk of CVD mortality after year 7 (subdistribution HR [sHR], 1.9; 95% CI, 1.4-2.7). However, there was a trend toward an inverse association between breast cancer status and CVD-related mortality in the first 7 years after diagnosis (sHR, 0.59; 95% CI, 0.40-0.87; P interaction =.001).
In line with these results, a 2020 study showed that breast cancer survivors had relatively low rates of CVD (5.8%; 95% CI, 3.8-7.7) within the first 5 years after diagnosis.6
There may be an obvious explanation for these temporal trends, according to Bradshaw et al.5 “This reduction in incident CVD mortality among survivors in the short term most likely reflects the influence of the major competing risk in this group (breast cancer-related death),” the authors wrote.