Long-term clinical outcomes of gastric mucosa-associated lymphoid tissue lymphoma: a retrospective study in regions with a high prevalence of Helicobacter pylori infection

Background: This study aims to investigate the treatment outcomes and identify risk factors influencing complete remission (CR) and relapse in patients with gastric MALT lymphoma across different treatment modalities. Methods: Three-hundred and ninety-eight patients with gastric MALT lymphoma were followed up for at least 48 weeks over 15 years in five tertiary hospitals in regions with high prevalence of Helicobacter pylori (H. pylori) infection. A retrospective review was performed using medical records. Results: A total of 398 patients were included, with a mean age at diagnosis of 55.5 ± 12.2 years and 176 (44.2%) were male. H. pylori infection was identified in 293 patients (73.6%), and 363 (91.2%) were diagnosed with stage IE. Significant differences in age, sex, and stage at diagnosis were observed between H. pylori-positive (HPP) and H. pylori-negative groups (HPN, all P < 0.05). In the HPP group, most patients underwent eradication therapy (98.9%), whereas 77.3% of HPN patients received eradication therapy, often combined with radiotherapy or chemotherapy. CR rate was 97.0%, with 98.3% in HPP and 93.3% in HPN (P = 0.018). During a median follow-up of 179 weeks, relapse occurred in 8.3% of patients, with 7.9% in HPP and 10.2% in HPN, respectively. Non-IE Modified Ann Arbor Stage (HR, 2.4; 95% CI, 1.0–5.5; P = 0.044), presence of lymphadenopathy (HR, 1.9; 95% CI, 1.2–3.1; P = 0.010), and lesions in multiple locations (HR, 2.1; 95% CI, 1.0 ~ 4.2; P = 0.037) at diagnosis correlated with a higher cumulative incidence of relapse (CIR). Multivariate Cox regression analysis showed that Non-IE Modified Ann Arbor Stage (aHR, 1.9; 95% CI, 1.2‒2.9; P = 0.004) and presence of lymphadenopathy (aHR, 1.5; 95% CI, 1.0‒2.3; P = 0.037) remained significantly correlated with higher CIR. Conclusions: Patients with gastric MALT lymphoma generally have a favorable prognosis, and H. pylori eradication can lead to CR, even in H. pylori-negative MALT lymphoma cases. Accurate staging at diagnosis is essential for optimal management, as disease stage and the presence of lymphadenopathy are key predictors of relapse.