The thesis of Daan Spoor investigated how large that risk is, which patients are most at risk, and how cardiac damage can be detected at an early stage.
In the research, 1,300 women treated for breast cancer were compared with a control group of 5,300 women of the same age who never had cancer. The women who had been treated for breast cancer had fewer common risk factors for heart disease, such as high blood pressure. Yet, heart failure was more common among them, suggesting that the treatment itself may play a role.
The researchers then improved how precisely they measure the dose reaching each individual part of the heart. With that, they built a model predicting heart attacks in the ten years after treatment. Above all, the combination of a high dose of radiation to the heart and the presence of calcium build-up in the coronary arteries were the main factors that raised the risk. A recalibration is necessary before the model can be considered for general clinical use.
MRI scans also contributed to picking up early signs of heart damage, before any symptoms. In roughly one in six women cardiac contraction was slightly reduced two years after radiotherapy, which was more prevalent in patients who received a higher dose. Such measurements reveal which parts of the heart are most vulnerable.
The predictive model could contribute to more personalised treatment by optimising radiation dose distributions to spare vulnerable parts of the heart, identifying patients most likely to benefit from proton therapy, and enabling targeted follow-up of patients at increased risk.
