A concerning connection: breast cancer survival and heart disease

There was a time when a diagnosis of breast cancer was pretty much a death sentence. Thankfully, that time has long since passed.

Since the 1980s, the death rate from breast cancer has declined significantly in North America. In the United States, there was a 43 percent decline in breast cancer deaths between 1989 and 2020. And in Canada, breast cancer deaths have declined by 49 percent since 1986.

If we stop right here, that’s certainly some great news. But even though fewer women are dying from breast cancer, their treatment may set them up for another disease…

A sharp spike in Canadian breast cancer survivors

While seeking statistics on the percentage of Canadian females with a history of breast cancer, the most recent figures that University of Toronto professor Amy Kirkham could find were from 2007.

“Nearly 15 years had passed and I could not find a more recent citation about the prevalence of breast cancer survivors in Canada,” says Kirkham. “Breast cancer mortality rates had continued to improve 26 percent over this time period, so I suspected that this number was no longer accurate.”

So she and her University of Toronto colleague Katarzyna Jerzak started a new study using the Canadian Cancer Society’s annual cancer statistic reports.

According to their findings, from 2007 to 2021, 2.1 percent of Canadian women were diagnosed with breast cancer, and 86 percent of these women would have survived their cancer by 2022.

“This indicates that the prevalence of breast cancer survivors in the Canadian female population has doubled and that there are 2.5 times more survivors since the last estimate in 2007,” Kirkham says.

Improved survivorship, but not out of the woods yet

In the 1980s, chemotherapy was established as a therapy for early breast cancer. Tamoxifen was one of the first drugs to specifically target estrogen-positive breast cancer. It was less expensive and had fewer side effects than other cancer treatments of that period.

Today, the standard course of treatment for most women with breast cancer in stages 1 through 3 is surgical removal of the cancer followed by radiation therapy. Many women also receive some sort of drug therapy, depending on the type of breast cancer they have.

Unfortunately, these treatments also cause short-term and long-term side effects.

According to Dr. Mandeep R. Mehra, executive director of the Center for Advanced Heart Disease at Brigham and Women’s Hospital and a professor at Harvard Medical School, “Almost every chemotherapy drug has some effect on the cardiovascular system, and most are not good. But with the new anticancer agents, an increasing amount of cardiac toxicity is being observed.”

One drug this is used to treat breast cancer, as well as several other types of cancer — doxorubicin — is a known cytotoxin that kills cancer cells very well, but also attacks healthy cells, including those in the heart.

“The most common cause of death in women with breast cancer is heart disease,” says Kirkham, whose research is focused on preventing and treating the risk of heart disease related to breast cancer treatment.

“Given the excess healthcare costs, potential for reduced contributions to the workforce and reduced quality of life associated with long-term side effects and risk of excess death among breast cancer survivors, our work highlights that there is a growing segment of the population who require services to support recovery following breast cancer treatment,” Kirkham says.

How survivors can protect their hearts

If you’re one of the millions of women who have survived or are surviving breast cancer, you may want to take extra precautions to protect your heart. The American Heart Association has a great guideline known as Life’s Essential 8 that provides steps to follow to lower the risk for heart disease by improving and maintaining cardiovascular health. These measures are:

Eat better. Follow a diet with plenty of whole foods, lots of fruits and vegetables, lean protein, nuts, seeds, and non-tropical oils such as olive and canola. All of these are incorporated into the DASH diet, which has been specifically engineered for optimal heart health.
Be more active. Adults should be getting get 2.5 hours of moderate or 75 minutes of vigorous physical activity every week. There are a couple of ways exercise can benefit cancer survivors: physical activity changes the metabolism of the immune system’s cytotoxic T cells and thereby improves their ability to attack cancer cells; during exercise, the body produces a protein called “Neuron-derived orphan receptor 1,” or NOR-. In research, it was shown to offer “broad protection against heart damage following cancer treatment.”
Quit tobacco. This includes the use of all chewing tobacco and inhaled nicotine delivery products. That means e-cigarettes and vaping devices, too.
Get healthy sleep. Most adults need 7 to 9 hours of sleep each night to promote healing and reduce the risk for chronic disease. If you’re regularly having trouble getting enough sleep, here are some natural ways you can help improve your sleep.
Manage weight. A useful measure to use in this regard is body mass index (BMI), a numerical value of your weight in relation to your height. A BMI of 25 is optimal.
Control cholesterol. High levels of non-HDL, the “bad” kind of cholesterol, can lead to heart disease. Getting regular exercise and following a healthy eating plan like the DASH diet can help control your cholesterol. Intermittent fasting has also proven effective at managing cholesterol as well as protecting against cancer.
Manage blood sugar. Consistent high levels of blood sugar can damage your heart over time. As with cholesterol, a healthy diet and regular exercise can go a long way toward keeping your blood sugar at optimal levels. And since breast cancer can raise your risk of developing diabetes, it’s doubly important to manage your blood glucose levels.
Manage blood pressure. Healthy blood pressure is important to overall well-being. Keeping your levels below 120/80 mm Hg is ideal.