Predicting heart risk before treatment for breast cancer

In the years after chemotherapy, women who survive breast cancer face uncertain effects on their cardiovascular health. The intensity of some cancer treatments raises the risk for problems that range from coronary disease to arrhythmia to stroke to heart failure.

The key question is: what exactly is the risk of heart damage from these treatments? And what should their doctors do to help them?

Dr. Husam Abdel-Qadir, a cardiologist-scientist at Women’s College Hospital and Peter Munk Cardiac Centre, led a study published in the prestigious European Heart Journal that has provided the means to an answer.

Analyzing 10 years of population data on 90,000 Ontario women with early breast cancer, Dr. Abdel-Qadir built a model that can predict each woman’s risk of suffering a major cardiovascular event within a decade.

“To actually quantify the risk for these women is new, and it expands the conversation to the overall questions of heart health,” said Dr. Abdel-Qadir, whose work in this area is part of the Ted Rogers Centre’s Cardiotoxicity Prevention Program. “Before even beginning cancer treatment, this tool can help inform treatment decisions that tailored to each individual patient.”

Gazing five and 10 years into the future

The risk prediction model was developed and validated by seeing how those 90,000 women interacted with the health-care system over a nine-year period. The research team could assess health status, who developed a serious heart problem, how long it took to develop, and what risk factors were involved.

They sought to design a tool that front-line care providers and even patients could use. So they took the data from their statistical model and distilled it into a risk score that could be easily interpreted.

It is essentially a calculator, assigning points based on such individual factors as age, blood pressure levels, existing heart issues, and comorbidities like diabetes and kidney disease. How many points any one woman generates can map their risk of suffering a serious adverse cardiovascular event – even death – at five and 10 years in the future.

The model is now proven capable of giving predictions for any random woman with early breast cancer. Most urgently, the study found that women who scored in the highest zone were over 40 times more likely to experience a major heart event than women in the lowest zone. Thankfully, most women have low scores, which should provide reassurance as they go on with the chemotherapy necessary to treat their breast cancer.

Empowering patients to manage their cardiovascular risk

“We hope this tool can be used quite widely to manage cardiovascular risk among women with breast cancer no matter where they live, rather than a model that requires trained specialists to perform,” says Dr. Abel-Qadir.

Anyone diagnosed with cancer must of course focus on its treatment right away. Through this model, women at low risk of future heart problems can feel empowered to get the necessary cancer therapy without concern over its cardiovascular impact. At the same time, the model will help identify the very few women whose risk of heart disease may be so high that cancer treatment should be modified.

The model’s lasting benefit is that it can be used to set up each patient for support in the right areas in the years to come. It can suggest to doctors when and how each woman should be followed up with, who requires the care of a cardiologist (even before chemotherapy), and precisely where near- and long-term treatment decisions should focus.

“The cardio-toxic impact of system therapies is a very important area, and it is deservedly gaining attention,” says Dr. Abel-Qadir. “I see rising interest among oncologists, who care about their patient’s entire health because they want to provide the best care possible. And breast cancer patients themselves are increasingly asking to be referred to our Centre to be evaluated.”

With this risk calculator, those patients can make personal decisions about their cancer therapy, and take steps to manage their own cardiovascular risk.