A MULTICENTER ANALYSIS OF PRIMARY GASTRIC LYMPHOMA IN BRAZILIAN CENTERS: FIRST RESULTS OF THE PELÉ STUDY (PRIMARY EXTRANODAL LYMPHOMA EFFORT)

Abstract

Objective: Evaluate clinical and epidemiological characteristics of patients with primary gastric lymphoma (PGL) within the PELÉ study. Methods: PELÉ is a multicenter study that aimed to collect information from patients with B cell primary extranodal lymphoma, in several hematological reference centers in Brazil. The data presented here is from the retrospective cohort of patients with PGL. This cohort is still collecting data, with several other centers awaiting ethics committee approval. Staging was done according to the Lugano classification of gastrointestinal tract lymphomas: stage I (confined to stomach), stage II (adjacent nodal involvement) and stage III (with other organs involved). Cases were collected from the last 15 years (2009 to 2024). Results: We evaluated 40 patients. Median age at diagnosis was 64 years-old (range 35-90), 55% were males and 72% of white skin color. Diffuse large B-cell lymphoma (DLBCL) was the diagnosis in 77.5% of cases and the remaining was extranodal marginal zone lymphoma (MALT). B symptoms occurred in 32% of cases and 15% had bulky disease. IPI was available in 31 cases with 20 patients (64%) as low-risk, 10 patients (32%) as low-intermediate and 1 patient as high-risk. Forty percent of patients were stage I, 27.5% stage II, 15% stage III and in 17.5% there were no complete information regarding the clinical stage. RCHOP was the main treatment choice (67.5% of patients), followed by RCVP (7.5%) and RminiCHOP (5%). Radiotherapy was done in 5 patients (12.5%), as consolidation of treatment in 3 cases and as second-line in 2 patients. Complete remission (CR) was achieved in 55% of patients, but in 22.5% of cases there were missing information about treatment response. Within the MALT lymphomas (9 patients), antibiotic therapy was the sole treatment in 4 patients. In 3 of those patients there was a response by GELA response criteria (2 residual responsive disease and 1 complete histological remission). Seven patients (17.5%) had confirmed relapse of the lymphoma, but none died. On the other hand, 4 patients died due to causes non-related to the lymphoma. The median follow-up was 35 months (range 1.3-194). Discussion: This cohort of PGL patients treated in Brazilian centers showed similar age and sex distribution compared to other cohorts of DLBCL. The population of the study were mainly of good prognosis, considering IPI, stage and presence of bulky disease. The CR rate was lower than expected from historical data. Patients with MALT lymphoma treated with antibiotics showed histological response in most cases, in line with the international literature. Conclusion: : The small sample size, short median follow-up and high proportion of cases with missing data are limitations of this study. The only deaths within the study period of observation were of causes non-related to lymphoma, even with 7 confirmed relapses. This points to an overall good prognosis, maybe related to the characteristics of the population.