Automated analysis of the routine scans of patients with breast cancer may help to predict which women have a greater risk of developing cardiovascular disease, according to research presented by Gal et al at the 12th European Breast Cancer Conference (Abstract 7).

Women who have been treated for breast cancer may have a higher risk of developing cardiovascular disease; in some patient groups, the risk of dying from cardiovascular disease is higher than the risk of dying from breast cancer.

This new study shows that it is possible to spot those at the greatest risk using computer analysis of the routine computed tomography (CT) scans used to plan cancer treatments.

Helena Verkooijen, MD, PhD

The research was presented by Helena Verkooijen, MD, PhD, of the Division of Imaging and Oncology at the University Medical Center Utrecht in The Netherlands. She said, “We've seen great improvement in breast cancer survival, thanks in part to better treatment. However, treatments have side effects and some treatments, such as radiotherapy and certain types of cancer drugs, can increase the risk of cardiovascular disease. In my opinion, treating breast cancer means finding the right balance between maximizing chances of tackling the tumor, while minimizing the risks of side effects, including the risk of cardiovascular disease.”

Coronary Artery Calcium Score

The study included around 14,000 patients with breast cancer who were treated with radiotherapy in three large hospitals in The Netherlands between 2005 and 2016.

Dr. Verkooijen and her colleagues used a measure called coronary artery calcium score. This is a calculation of the amount of calcium in the walls of the heart's arteries and it is known to be strong risk factor in cardiovascular disease, because calcifications can lead to narrowing or blocking of the blood vessels.

The researchers developed a deep learning algorithm that could gauge the presence and extent of coronary artery calcifications from the CT scans that were already being carried out to help plan each woman's radiotherapy treatment. This allowed them to automate the measurement of coronary artery calcium for all the women with only minimal extra workload.

Risk of Heart Disease

Researchers followed the women for an average of 52 months to see whether any of them developed cardiovascular disease. In women with no calcifications (a score of 0), 5% went on to be hospitalized or to die from cardiovascular disease. In women with a score of between 1 and 10, 8.9% were hospitalized with or died from cardiovascular disease. In women with a score of 11 to 100, the figure was 13.5%; in women with a score of 101 to 400, it was 17.5%; and in women with a score above 400, it was 28.3%.

When researchers took into account women’s ages and the year they were diagnosed, they found a 3.7 times greater risk of cardiovascular disease in women with the highest score (above 400) compared with women with no calcifications. In women who were treated with anthracyclines, the association between high coronary artery calcium score and cardiovascular risk was even stronger.

The researchers acknowledge that they were unable to take other cardiovascular disease risk factors, such as smoking, high blood pressure, and diabetes, into account in this study, although these are factors they are looking at in another study.

Dr. Verkooijen said, “We believe this is the first time anyone has conducted a large-scale study like this. We've shown that we can use routine CT scans to indicate which [patients with] breast cancer are most likely to develop cardiovascular disease. Now we need to do more research to find out what can be done to help minimize this risk—for instance, whether patients' cardiovascular health should be monitored or treated."

The researchers are now working to get their technique for predicting cardiovascular disease risk into use in several radiotherapy units in The Netherlands. Patients taking part in this study who are found have an increased risk will be offered further cardiovascular screening and lifestyle advice, and their coronary artery calcium score will be used in planning their breast cancer treatment.

Disclosure: For full disclosures of the study authors, visit cm.eortc.org.