Study on the effectiveness of radiation therapy for metastases in addition to standard drug therapy

Breast cancer is a malignant disease of the breast tissue characterized by the uncontrolled proliferation of breast cells. Treatment of the disease depends on numerous factors. If the cancer has also spread to other parts of the body, this is referred to as metastasis. This corresponds to stage 4 of the disease. For the OLIGOMA study, it is important that the cancer has spread to no more than five sites in the body. This is referred to as “oligometastatic breast cancer.” This form of breast cancer has a better prognosis than more advanced metastatic breast cancer, and there is evidence that targeted treatment of the metastases could positively influence the course of the disease.

The current standard of care for oligometastatic breast cancer (Stage 4) is drug therapy (hormone therapy, chemotherapy, antibody therapy, and, if necessary, treatment with other medications). The choice of medications depends on the specific characteristics of the breast cancer, such as whether it has hormone receptors, which would allow for the use of targeted therapies. The exact type of treatment is not specified in the OLIGOMA study and is administered by the treating physician in accordance with established standards. In the OLIGOMA study, so-called ablative radiation therapy is used in addition to standard therapy. This is a highly precise form of radiation therapy in which only the metastases are specifically treated with high doses. Various techniques, such as radiosurgery, stereotactic radiation therapy, or intensity-modulated radiation therapy (IMRT), are used depending on the location and size of the metastases. These techniques are already well-established and are routinely used to treat various types of cancer. They enable large doses of radiation to be delivered with high precision to the desired sites, effectively destroying the metastases while sparing the surrounding tissue.

The OLIGOMA study compares two groups: one group receives standard therapy, while the other group also receives targeted radiation therapy for the metastases. The goal is to determine whether the additional radiation therapy delays the progression of the disease and improves quality of life. Patients are randomized—that is, assigned at random to one of the two groups. The study is open-label, meaning that both the patients and the treating physicians know which treatment is being administered. The exact type, frequency, and duration of radiation therapy will be determined individually for each patient.

Women aged 18 and older who are not pregnant or breastfeeding are eligible to participate in the study. They must have at least one but no more than five metastases, of which no more than three may be located in the brain. Participation is only possible if all metastases can be irradiated without exceeding the dose limit for the respective organ. The specific type of breast cancer is neither an inclusion nor an exclusion criterion. Patients may be excluded if they have already received radiation therapy that could interfere with the study treatment. Additionally, participation is not possible if the patient has exclusively brain metastases or exclusively metastases in the regional lymph nodes.