A Study of Response Adapted Ultra Low Dose 4 Gy Radiation for Definitive Therapy of Marginal Zone Lymphoma

This study tests whether a very low dose of radiation (4 Gy — much lower than standard doses) can effectively treat marginal zone lymphoma, a slow-growing blood cancer, with the option to add a slightly higher dose only if needed based on early response. **You may be eligible if...** - You are 18 or older - You have been diagnosed with marginal zone lymphoma (stage I or II) - You still have measurable disease that can be evaluated - You are planned to be treated with radiation alone (no planned chemotherapy before the first follow-up) - Prior treatments are allowed as long as disease is still present before starting radiation **You may NOT be eligible if...** - You have a different type of lymphoma - You have psychiatric or social problems that would prevent you from following the study requirements - You are pregnant - You have previously received radiation to the same area and further treatment would exceed safe limits - You have active scleroderma (a connective tissue disease) Talk to your doctor to see if this trial is right for you.