OBJECTIVETo analyze the clinical and pathological features, molecular biological markers and prognosis of primary gastrointestinal diffuse large B-cell lymphoma (DLBCL).

METHODSA retrospective study was conducted in 92 cases of primary gastrointestinal DLBCL. The data of clinical characteristics, pathological and immunohistochemical features were analyzed. The relationship between different factors at diagnosis and prognosis were studied.

RESULTSOf the 92 patients, the male-female ratio was 1.56:1 with a median age of 59(7-89) years. The most frequently involved site was stomach (50.0%), followed by small intestine (15.2%), colon (12.0%), ileocecum (10.9%) and multiple gastrointestinal tract involvements (9.8%). The ratio of non-germinal center B cell (non-GCB) subtype to germinal center B cell (GCB) was 2:1. Among the cases, Ki-67 had a high level expression with a median positive rate >80%. Positive expression of Bcl-2 was detected in 52.1% cases (25/48). Evidence of Helicobacter pylori (Hp) infections was detected in 34.0% cases with stomach involvement. Of the patients, 75 were included in a follow-up study with a median time of 48 months (3-130 months). The complete remission(CR)rate was 66.7%(50/75),the partial remission (PR) rate was 22.7% (17/75) and the overall response rate was 89.4% (67/75). The 1-, 3- and 5- year survival rates of the patients were 85.3%, 66.2% and 60.5%, respectively. The incidence of secondary malignancy after chemotherapy was 2.7%. The multivariate analysis indicated that primary colic DLBCL or multiple involvements of gastrointestinal tract and low serum albumin level (<35 g/L) at diagnosis were independently associated with poor outcome. Patients who received chemotherapy combined with rituximab (43 cases) had a higher CR rate (79.1% vs 46.9%, P=0.008) and 5-year overall survival (77.5% vs 53.1%, P=0.0045) than those without rituximab (32 case).

CONCLUSIONPrimary gastrointestinal DLBCL was a highly invasive and heterogeneous malignancy. In our data, the proportion of non-GCB subtype was higher. Primary colic DLBCL and those with multiple involvements of gastrointestinal tract had poor survival. Low serum albumin at diagnosis indicated poor outcome. Rituximab treatment in addition to chemotherapy might help to improve the clinical outcome. Further prospective trails were needed to confirm our results.