Observational Study on the Genetic Characteristics of Tumor Cells in the Breast and, Where Applicable, Metastases in Invasive Lobular Breast Cancer (ILC)

Invasive lobular carcinoma (ILC) is a rarer form of breast cancer that originates from cells in the lobules. It differs from other forms of breast cancer in appearance, behavior, and, to some extent, progression. Because of these differences, initial approaches are already being taken to treat patients differently. The cause of cancer in general is the degeneration of cells, leading to uncontrolled growth. This is due to changes in the genetic blueprint (genome, DNA) of the affected cells. If the cancer forms secondary tumors (metastases) in the body, new changes (mutations) could also occur in the genetic material of the cancer cells, resulting in differences between the original tumor and the metastases. In the case of invasive lobular breast cancer, this could explain why treatment often yields poorer results compared to other types of breast cancer. However, there have been no comprehensive tissue analyses to date examining whether, in invasive lobular breast cancer, the genetic makeup of the cells actually differs between the tumor in the breast and the metastases.

The goal of the ILC registry study is to compare disease courses in order to better and earlier identify patients at increased risk over the long term. To this end, the study will investigate whether there are different mutations that occur in the primary tumor or in metastases and influence the course of the disease. Ideally, the study aims to identify mutations associated with a higher risk of metastasis. The study is a non-interventional observational study and aims to create a registry of cases of invasive lobular breast cancer. Therefore, no new medications or treatment modalities are being investigated.

Adult women with invasive lobular breast cancer are eligible to participate.

As part of the registry study, patients can also participate in a biannual online survey (via email) that assesses disease progression, lifestyle, well-being, and quality of life. This will help us better understand what the disease means for patients in their daily lives, so we can identify areas for improvement—particularly in counseling and follow-up care.

The survey consists of a more detailed initial survey and a short follow-up survey, which is repeated every 6 months. The data is collected in pseudonymized form.