Postmenopausal breast cancer survivors are at greater risk for cardiovascular disease than are their peers without breast cancer, according to a new study of nearly 300 women.

Previous studies have shown that cardiovascular risk is greater among postmenopausal women treated for breast cancer compared with those without cancer, but specific risk factors have not been well studied, wrote Daniel de Araujo Brito Buttros, MD, of Paulista State University, Sao Paulo, Brazil, and colleagues.

In a study published in Menopause, the researchers evaluated several CVD risk factors in 96 postmenopausal women with breast cancer and 192 women without breast cancer, including metabolic syndrome, subclinical atherosclerosis, and heat shock proteins (HSP) 60 and 70.

Overall, breast cancer patients had significantly higher HSP60 levels and lower HSP70 levels than those of their cancer-free peers. These two proteins have an antagonistic relationship in cardiovascular disease, with HSP60 considered a risk factor for CVD, and HSP70 considered a protective factor. Average HSP60 levels for the breast cancer and control groups were 35 ng/mL and 10.8 ng/mL, respectively; average HSP70 levels were 0.5 ng/mL and 1.3 ng/mL, respectively.

Both diabetes and metabolic syndrome were significantly more common among breast cancer patients vs. controls (19.8% vs. 6.8% and 54.2% vs. 30.7%, respectively). Carotid artery plaque also was more common in breast cancer patients vs. controls (19.8% vs. 9.4%, respectively, P = 0.013).

In addition, systolic and diastolic blood pressure levels were significantly higher among the breast cancer patients, as were triglycerides and glucose.

The findings were limited by several factors including the cross-sectional design that could not prove a causal relationship between CVD risk and breast cancer, the researchers noted.

However, the results demonstrate the increased CVD risk for breast cancer patients, and “[therefore], women diagnosed with breast cancer might receive multidisciplinary care, including cardiology consultation at the time of breast cancer diagnosis and also during oncologic follow-up visits,” they said.

“Heart disease appears more commonly in women treated for breast cancer because of the toxicities of chemotherapy, radiation therapy, and use of aromatase inhibitors, which lower estrogen. Heart-healthy lifestyle modifications will decrease both the risk of recurrent breast cancer and the risk of developing heart disease,” JoAnn Pinkerton, MD, executive director of the North American Menopause Society, said in a statement. “Women should schedule a cardiology consultation when breast cancer is diagnosed and continue with ongoing follow-up after cancer treatments are completed,” she emphasized.

The researchers had no financial conflicts to disclose.

SOURCE: Buttros DAB et al. Menopause. 2019. doi: 10.1097/GME.0000000000001348.