EFFICACY OF ULTRA-LOW-DOSE RADIOTHERAPY IN MALT LYMPHOMA: REAL-WORLD DATA FROM A BRAZILIAN CANCER CENTER
- 1AC Camargo Cancer Center, São Paulo, SP, Brazil
Abstract
Background: Extranodal marginal zone lymphomas of mucosa-associated lymphoid tissue (MALT) are rare, accounting for 7–8% of non-Hodgkin lymphomas, and are commonly associated with chronic antigenic stimulation from infections or autoimmune conditions. The stomach is the most frequently affected site, particularly due to its association with H. pylori. Eradication therapy can induce remission in approximately 75% of cases. Radiotherapy (RT) at 24–30 Gy is highly effective after treatment failure. To reduce toxicity, ultra-low-dose RT (4 Gy) has been investigated, with high response rates and the possibility of additional RT in patients without complete response. Aim: To describe the epidemiological characteristics and treatment outcomes of patients with newly diagnosed MALT lymphoma treated with ultra-low-dose RT at a Brazilian center. Methods: We retrospectively collected data from patients diagnosed with MALT lymphoma between August 2016 and September 2025 who were either H. pylori-negative or refractory to eradication therapy. Results: Sixteen patients were included. Most cases (93.75%) were gastric MALT lymphomas, with one pulmonary case. Median age was 59.5 years (36–78), and 10/16 (62.5%) patients were male. Ten patients underwent PET imaging: 9 had localized stage I disease and 1 had advanced pulmonary MALT lymphoma. LDH was available in 11/16 (68.7%) patients, with a median of 195 U/L (139–275). Among these, 10/11 (90.9%) had low-risk MALT-IPI and 1/11 (9.1%) intermediate-risk disease. Of 15 patients tested for H. pylori, 13 (86.7%) were negative. Only 1/5 patients tested for t(11;18) was positive. Empirical H. pylori eradication therapy was administered to 75% of patients. Ultra-low-dose RT was administered to 15/16 (93.75%) patients, while 1 received conventional-dose RT. At 3–4 months, 13 patients underwent endoscopic reassessment: 9/13 (69.2%) achieved complete response, 1/13 (7.7%) partial response, 2/13 (15.4%) stable disease, and 1/13 (7.7%) progressive disease. Patients without complete response received an additional 20 Gy. After a median follow-up of 16.5 months, 4/16 (25%) patients experienced disease progression, with a median time to progression of 10.5 months. No deaths or histological transformations occurred. Conclusion: Ultra-low-dose RT demonstrated high efficacy and disease control in newly diagnosed MALT lymphoma. Most patients achieved complete response, while residual or progressive disease could be managed with additional RT. These real-world findings support response-adapted ultra-low-dose RT as a treatment de-escalation strategy for selected patients with localized MALT lymphoma.
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BibTeX
@article{garcia2026efficacy,
title = {{EFFICACY OF ULTRA-LOW-DOSE RADIOTHERAPY IN MALT LYMPHOMA: REAL-WORLD DATA FROM A BRAZILIAN CANCER CENTER}},
author = {Matheus DE LIMA GARCIA and Julia AITH BALTHAZAR and Giovanna ALVES PERUZINI and Gabrielle Hyllen NEVES RODRIGUES VIEIRA and Julia CURI AMARANTE and Thais FISCHER and Jayr SCHIMDT FILHO and Talita SILVEIRA},
journal = {Hematology, Transfusion and Cell Therapy},
year = {2026},
month = oct,
doi = {10.1016/j.htct.2026.107757},
url = {https://doi.org/10.1016/j.htct.2026.107757},
note = {CC BY},
}
RIS
TY - JOUR
TI - EFFICACY OF ULTRA-LOW-DOSE RADIOTHERAPY IN MALT LYMPHOMA: REAL-WORLD DATA FROM A BRAZILIAN CANCER CENTER
AU - Matheus DE LIMA GARCIA
AU - Julia AITH BALTHAZAR
AU - Giovanna ALVES PERUZINI
AU - Gabrielle Hyllen NEVES RODRIGUES VIEIRA
AU - Julia CURI AMARANTE
AU - Thais FISCHER
AU - Jayr SCHIMDT FILHO
AU - Talita SILVEIRA
PY - 2026
DA - 2026/10/23
JO - Hematology, Transfusion and Cell Therapy
DO - 10.1016/j.htct.2026.107757
UR - https://doi.org/10.1016/j.htct.2026.107757
AB - Background: Extranodal marginal zone lymphomas of mucosa-associated lymphoid tissue (MALT) are rare, accounting for 7–8% of non-Hodgkin lymphomas, and are commonly associated with chronic antigenic stimulation from infections or autoimmune conditions. The stomach is the most frequently affected site, particularly due to its association with H. pylori. Eradication therapy can induce remission in approximately 75% of cases. Radiotherapy (RT) at 24–30 Gy is highly effective after treatment failure. To reduce toxicity, ultra-low-dose RT (4 Gy) has been investigated, with high response rates and the possibility of additional RT in patients without complete response. Aim: To describe the epidemiological characteristics and treatment outcomes of patients with newly diagnosed MALT lymphoma treated with ultra-low-dose RT at a Brazilian center. Methods: We retrospectively collected data from patients diagnosed with MALT lymphoma between August 2016 and September 2025 who were either H. pylori-negative or refractory to eradication therapy. Results: Sixteen patients were included. Most cases (93.75%) were gastric MALT lymphomas, with one pulmonary case. Median age was 59.5 years (36–78), and 10/16 (62.5%) patients were male. Ten patients underwent PET imaging: 9 had localized stage I disease and 1 had advanced pulmonary MALT lymphoma. LDH was available in 11/16 (68.7%) patients, with a median of 195 U/L (139–275). Among these, 10/11 (90.9%) had low-risk MALT-IPI and 1/11 (9.1%) intermediate-risk disease. Of 15 patients tested for H. pylori, 13 (86.7%) were negative. Only 1/5 patients tested for t(11;18) was positive. Empirical H. pylori eradication therapy was administered to 75% of patients. Ultra-low-dose RT was administered to 15/16 (93.75%) patients, while 1 received conventional-dose RT. At 3–4 months, 13 patients underwent endoscopic reassessment: 9/13 (69.2%) achieved complete response, 1/13 (7.7%) partial response, 2/13 (15.4%) stable disease, and 1/13 (7.7%) progressive disease. Patients without complete response received an additional 20 Gy. After a median follow-up of 16.5 months, 4/16 (25%) patients experienced disease progression, with a median time to progression of 10.5 months. No deaths or histological transformations occurred. Conclusion: Ultra-low-dose RT demonstrated high efficacy and disease control in newly diagnosed MALT lymphoma. Most patients achieved complete response, while residual or progressive disease could be managed with additional RT. These real-world findings support response-adapted ultra-low-dose RT as a treatment de-escalation strategy for selected patients with localized MALT lymphoma.
SN - 2531-1379
SN - 2531-1387
ER -