P-160 Primary gastrointestinal lymphoma in Latin American patients. A 10-year follow-up

Abstract

Gastrointestinal lymphomas constitute 10-15% of non-Hodgkin´s Lymphomas and 30-40% of extra-nodal lymphomas. Primary gastric lymphoma (PGL) is the most common site (75%) and is most diagnosed in man with a mean age of 60 years. Even when prognosis is favorable at early stages of disease, most patients are diagnosed with advanced disease and treatment pattern remains under debate with not enough evidence to support optimal management. The aim of this study was to describe incidence, clinicopathological characteristics, treatment modalities and outcome of Latin American patients with PGL treated at the National Cancer Institute. Retrospective, observational study. Included patients diagnosed with EGJ adenocarcinoma, treated at the National Cancer Institute between 2011 and 2021. Statistical analysis required: X2 and t test, Kaplan Meier, Log Rank and Cox Regression. Statistical significance differences were assessed when p was bilaterally < 0.05. A total of 62 patients were included in the analysis. The 63%(n=39) of cases were male with a median age at diagnosis of 61 (26-83) years old. Comorbidities included type 2. Diabetes (14%), and systemic arterial hypertension (21%). Additionally, 42% of patients had history of smoking and alcoholism. History of disease pretreatment was a median of 3.5 (1-40). According to symptomatology, the most prevalent symptoms were weight loss (85%, n= 53), abdominal pain (80%, n= 50), bleeding (60%, n= 37) and vomiting (58%, n= 136). Regarding histology the 90%(n=56) of cases were B cell lineage. Most common immunohistochemistry markers were CD20 (95%; n=59), BCL6 (63%; n=39), and CD10 (47%; n=29), also c-MYC rearrangement was found in (21%; n=13). Respecting clinical stage, most patients were diagnosed at metastatic disease (44%; n=27), the most common extranodal site of disease was the liver (76%). Oncological treatment, the 89% (n=55) were treated with chemotherapy, being CHOP-R scheme the most common modality of treatment. Moreover, the 29% (n=18), received radiotherapy. At OS analysis, the Five-year-OS rate for total population was 54% (95%CI 54.1-85.52). Furthermore, OS analysis was conducted comparing clinical stage, clinical stage I-III patients did not reach the median-OS, compared to patients with metastatic PGL was 11 months (p=0.50). PGL is an uncommon neoplasia known for its bad prognosis and outcome, due most of PGL patients are diagnosed at metastatic disease and historically the management of PGL has been controversial. Nevertheless, the addition of Rituximab to standard chemotherapy have demonstrated to significantly increase the OS of patients. Further studies remain necessary to promote an early diagnosis and to establish the optimal management of PGL.