ULTRA-LOW-DOSE radiotherapy (4 Gy) is effective for treating gastric mucosa-associated lymphoid tissue (MALT) lymphoma. Researchers aimed to investigate how to ensure the safety of 4 Gy whilst maintaining high efficacy, in a patient cohort with newly diagnosed or relapsed Helicobacter pylori-negative gastric MALT lymphoma.
Between March 2019 and October 2021, the study enrolled 24 patients, with a median age of 67. The majority of patients (83%) had stage I disease, with a small number presenting with stage II or IV. Patients underwent external beam photon-based radiotherapy, receiving a total dose of 4 Gy administered in two fractions. The primary endpoint was achieving a complete gastric response one year after treatment. The results were promising: 83% of patients exhibited a complete response to the initial 4 Gy treatment. Specifically, 16 patients achieved a complete response within 3–4 months, while an additional four patients responded within 9–13 months.
Patients who did not achieve a complete response with the initial treatment were monitored and administered an additional 20 Gy if necessary. Four patients required this additional dose, all of whom achieved a complete response subsequently. The study reported a 3-year local control rate of 96%, with only one local relapse successfully managed with further radiotherapy.
The treatment was well-tolerated, with the most common adverse events being grade 1 nausea (observed in 38% of patients receiving 4 Gy and 50% receiving 20 Gy) and grade 1 abdominal pain (21% of the 4 Gy group). Importantly, no grade 3 or higher adverse events or treatment-related deaths were reported.
The findings suggest that a response-adapted radiotherapy approach, starting with an ultra-low dose of 4 Gy, can effectively manage gastric MALT lymphoma while minimizing treatment-related toxicity. This strategy allows for selective administration of additional radiotherapy, potentially sparing patients from unnecessary treatment-related side effects.
Reference
Gunther JR et al. Response-adapted ultra-low-dose 4 Gy radiation as definitive therapy of gastric MALT lymphoma: a single-centre, pilot trial. Lancet Haematol. 2024;DOI:10.1016/S252-3026(24)00133-9.
