Lower Radiation Dose for Radiation Therapy of Marginal Zone Lymphoma and Follicular Lymphoma Involving the Gastrointestinal Tract

Follicular lymphoma (FL) and marginal zone lymphoma (MZL) are malignant diseases of the lymphatic system and are classified as non-Hodgkin lymphomas. These conditions involve the uncontrolled proliferation of B lymphocytes. Lymphocytes are a type of white blood cell that is part of the immune system. Symptoms of these diseases may include fatigue, weakness, anemia, weight loss, abdominal pain, and swollen lymph nodes. The exact causes are unknown, but genetic factors, chronic infections, and immune system disorders may play a role.

Depending on how far the diseases have progressed, lymphomas are classified into different stages. In stages I and II, a limited region is affected, such as the gastrointestinal tract. Involved-site radiation therapy (ISRT) is part of the standard treatment for FL and MZL in stages I and II. This is a form of radiation therapy in which the affected areas are irradiated. The radiation dose is measured in grays (Gy). The total dose is divided among several treatment sessions. Currently, the standard dose for treating FL and MZL is 30 Gy. It is possible that comparable results could be achieved with a lower radiation dose. A reduction in the radiation dose should be pursued to minimize the risk of potential side effects, especially in the long term.

The aim of this Phase 2 study is to investigate the efficacy and safety of low-dose radiation therapy totaling 20 Gy and to compare it with the current standard of care based on existing data. The study itself therefore does not include a control group. The study thus consists of a single treatment group and is open-label, meaning that both the medical staff and the patient are aware that the radiation therapy is being administered at a lower dose. As part of the study, daily radiation doses of 2 Gy are administered over a total of 10 sessions. In addition, blood samples are collected at enrollment, after the second, fifth, and final radiation sessions, and 3 and 6 months after treatment. Treatment and follow-up as part of the study continue for up to 6 months after the end of therapy, during which the efficacy of the therapy and the occurrence of side effects are evaluated. The primary endpoint of the study is the response rate to therapy after 6 months.

Patients aged 18 and older with stage I or II MZL or FL in the stomach or duodenum are eligible to participate in the study.