Many U.S. women with breast cancer ultimately die of other causes, a new study finds, highlighting the need for survivors and their doctors to pay attention to overall health.
In recent decades, advances in breast cancer treatment have meant that more women are becoming long-term survivors, which also means that other health issues will become important in their lives.
In the new study, researchers found that among breast cancer patients who died five to 10 years after their diagnosis, only 38% of deaths were caused by the disease.
And among women who died beyond the 10-year mark, breast cancer was the cause less than one-quarter of the time. Instead, the majority of those women died of heart disease, stroke, Alzheimer’s or other non-cancer conditions.
“We’ve known that breast cancer survival is improving, and that many women are living longer,” said senior researcher Dr. Mohamad Bassam Sonbol, an oncologist at the Mayo Clinic in Phoenix, Ariz.
Women diagnosed with earlier-stage breast cancer (confined to the breast) are 99% as likely as other women to be alive five years later, according to the nonprofit, Susan G. Komen. And right now, the United States alone has about 3.8 million breast cancer survivors.
The new findings give a clearer picture of what those women ultimately die from, according to Sonbol. And they underscore the importance of paying attention to overall health.
“As oncologists, we tend to focus mainly on the cancer,” he said. “But over time, the risk of death from breast cancer goes down substantially. There needs to be a focus on primary care, too.”
That includes ensuring women get recommended screenings for other cancers, according to Sonbol. They should also eat a healthy diet, get regular exercise and control heart disease risk factors, including high blood pressure and high cholesterol, he said.
The findings — published online Dec. 16 in the journal Cancer — are based on medical records from more than 754,000 U.S. women who were diagnosed with breast cancer between 2000 and 2015. By 2015, just under one-quarter had died.
A majority of those deaths — over 60% — happened within five years of the diagnosis. In that time frame, breast cancer was the most common cause of death, while just under one-third of women died from non-cancer causes.
Beyond year five, the picture shifted. Among women who died five to 10 years after their diagnosis, almost half died of non-cancer causes, while 13% died of other cancer types. And when women died more than 10 years out, 61% succumbed to conditions like heart disease, stroke and Alzheimer’s; another 15% died of other cancers, the findings showed.
In some cases, those conditions can reflect long-term effects of treatment, Sonbol said. Certain therapies — including some drugs and radiation to the left side of the chest — can damage the heart. Meanwhile, radiation and certain drugs or hormone therapies can raise the odds of a second, unrelated cancer — affecting the lungs, uterus or blood, for instance.
Some medical centers have “survivor clinics,” where cancer patients can receive long-term follow-up care, noted Dr. Len Lichtenfeld, deputy chief medical officer at the American Cancer Society.
More often, though, survivors go back to the “mainstream” of primary care, he said. And their doctors may not be aware of the long-term risks associated with the cancer treatments they received, or the kinds of screenings and other follow-up they may need.
Even in the age of electronic medical records, don’t assume your doctors know everything about your history, Lichtenfeld stressed.
“Patients should have a full understanding, from their cancer care team, of the specific long-term risks associated with their disease and their treatment,” he said.
And get it in writing, he advised: “That way, you can hold it in your hand, and take it to your primary care provider.”
Ideally, the cancer care team should provide that type of information. If not, Lichtenfeld said, ask for it.
“This is an area where it’s very important to be your own advocate,” he said.
The American Cancer Society has resources for survivors.