Pattern of failure and optimal treatment strategy for primary gastric diffuse large B-cell lymphoma treated with R-CHOP chemotherapy

Purpose: The optimal treatment for primary gastric diffuse large B-cell lymphoma (PG-DLBCL) is still unknown. We evaluated unfavorable prognostic factors and pattern of failure in PG-DLBCL to determine the optimal treatment strategy. Methods: Between April 2001 and November 2018, 120 patients with complete remission following rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisolone (R-CHOP) chemotherapy were retrospectively reviewed. According to the Lugano staging system, 80 patients (66.7%) had localized disease and 40 patients (33.3%) had advanced disease. A total of 93 (77.5%) patients had single gastric lesion and 27 (22.5%) patients had multiple gastric lesions. Ninety patients (75%) were treated with R-CHOP chemotherapy alone and 30 patients (25%) received R-CHOP chemotherapy with additional local treatment for gastric lesions. Results: The 5-year locoregional failure-free survival (LRFS), progression-free survival (PFS), and overall survival (OS) rates in patients treated with R-CHOP chemotherapy with local treatment were 100%, 100%, and 100%, respectively, whereas the LRFS, PFS, and OS rates in patients treated with R-CHOP chemotherapy alone were 86.3%, 78.2%, and 87.4%, respectively (p = 0.031, p = 0.095, and p = 0.025, respectively). During the follow-up period, 17 patients (14.2%) had disease recurrence. Only 3 of the 17 patients had relapse in a completely new site without relapse in the initial involved site. All, except 2, cases of local recurrence included gastric failure. In the multivariate analysis, performance status and number of gastric lesions were independent prognostic factors for treatment outcome. Conclusions: Patients with complete remission following R-CHOP chemotherapy showed a good prognosis. The main pattern of failure in patients with PG-DLBCL was local recurrence, especially in the stomach. Patients who received local treatment for gastric lesions showed improved gastric control. Therefore, in patients with unfavorable prognostic factors, we recommend R-CHOP chemotherapy with additional local treatment for gastric lesions.