Breast cancer treatment, including radiation and certain types of chemotherapy, has been linked with subsequent heart conditions. A new study finds, though, that existing heart conditions may also, in turn, impact breast cancer.

Researchers at the University of Texas MD Anderson Cancer Center recently investigated the link between advanced breast cancer and cardiovascular disease (CVD), specifically looking at whether CVD impacts when the cancer is diagnosed. The findings, published in the journal JAMA Network Open, showed that patients diagnosed with later stage breast cancer, stages III and IV, were 10% more likely to already have CVD than those diagnosed at stage I or II. The researchers say this is especially concerning, considering that CVD is linked with tumor growth and spread.

Dr. Kevin Nead, the study’s senior author and assistant professor of epidemiology and radiation oncology, explains, “Cardiovascular disease can induce an immunosuppressive state, potentially fostering accelerated breast tumor cell growth and spread. Our findings suggest that women with cardiovascular disease may be more likely to be diagnosed with advanced breast cancer, highlighting a potential connection between the two.”

Their study involved nearly 19,300 female breast cancer patients, all at least 66 years of age, from the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked databases from 2009 to 2020. About half also had CVD.

The findings showed that patients diagnosed at stage III or IV were 10% more likely to have CVD before the diagnosis, compared to earlier stage patients, and this was particularly true for a specific type of cancer: hormone receptor-positive, HER2-negative, which researchers point out accounts for about 70% of overall cases.

The researchers say their findings suggest CVD patients may be more apt to face a later stage breast cancer diagnosis, but further research is needed.

Dr. Nead explains, “The study could help inform personalized screening strategies, as it suggests that individuals with CVD may benefit from earlier or more frequent breast cancer screenings to catch the disease at an earlier, more treatable stage.”

Some limitations of the study include that it’s observational and doesn’t show that CVD causes advanced cancer, that there may have been misclassification of CVD, the study group was primarily white, and that the research didn’t control for possible confounding factors like smoking. You can read the whole study here.