Study on the Effect of Breath-Rhythm-Controlled Radiation Therapy to the Left Breast on Radiation-Induced Heart Damage

The treatment of breast cancer consists of several components, including radiation therapy to the breast. This is done to destroy any remaining tumor cells that were not removed during surgery. Particularly in cases of left-sided breast cancer, the necessary radiation therapy can put the heart at risk because it is located near the irradiated area. Radiation damage to the heart can lead to serious cardiovascular diseases, which often do not appear until years after treatment. An unavoidable side effect of radiation therapy is that healthy tissue is also exposed to radiation and can therefore be damaged. Since breathing causes the chest and the breast to move along with the irradiated area, the radiation cannot be delivered as precisely as desired. Techniques have therefore been developed (known as gated radiotherapy) to make radiation delivery as precise as possible.

The goal of the GATTUM study is to investigate breath-gated radiotherapy for left-sided breast cancer. This technique aims to protect the heart during radiation therapy by delivering the radiation only during specific phases of the breath, when the heart is as far away from the chest wall as possible. The study investigates whether this technique is actually necessary and how great the distance between the chest wall and the heart must be during radiation therapy to optimally protect the heart. The goal is to further improve radiation therapy for breast cancer and to protect patients’ heart health in the long term.

The study is an observational study in which 150 patients will be monitored over a period of three years. The key measurements are the distance from the heart to the chest wall and to the breast tissue. Only patients between the ages of 18 and 60 who have undergone breast-conserving surgery and have no affected lymph nodes are eligible to participate. Women who have had a complete removal of the breast (mastectomy) or those with affected lymph nodes are excluded from participation.