CHOP Followed by Radiotherapy for Localized Aggressive Primary Gastric Lymphoma: Results of a Multi Center Phase II Study.

Classically, the treatment of localized gastric lymphoma was based on surgery, alone or followed by chemotherapy and/or radiation therapy (RT). The need for surgery as a diagnostic procedure and staging tool has decreased. CHOP chemotherapy followed by RT has been a standard first-line treatment for localized stage I–II nodal Diffuse Large B-cell Lymphoma (DLBL). The purpose of this study is to define role of CHOP followed by RT for localized high-grade primary gastric lymphoma, just as nodal localized DLBL. The patient population in this study consisted of newly diagnosed patients of at least 18 years of age with histologically documented localized high-grade primary gastric lymphoma. The stage of each patient’s disease was assigned according to the Ann Arbor staging system as modified by Musshoff. Patients were expected to have performance status of 0, 1, or 2 according to the World Health Organization scale. Patients were to receive a total of four cycle of CHOP chemotherapy given every 21 days. The planned doses of radiation were total 40.0 Gy. From August 1998 to December 2003, 55 patients were registered. Five patients (9%) were excluded from analysis due to withdrawal of consent (n=1), ineligibility (n=2), incorrect histology (n=1), and inadequate data for response evaluation (n=1). Fifty patients were included in this analysis. The median age of the 25 female and 25 male patients was 54.5 years (range 21–73 years), and most of the patients (92%) had a good performance status (0 or 1). All of the patients were DLBL patients. Among these 50 DLBL patients, eight patients included low-grade lymphoma component. The overall response rate to the CHOP chemotherapy was 94% (95% confidence interval, 87% to 100%) in the intent-to-treat population. Forty- one (82%) of 50 patients (95% confidence interval, 71% to 93%) achieved complete response (CR), and 6 patients (12%) had partial response (PR). Three patients were not evaluable. Finishing RT, five patients who were in PR after chemotherapy eventually converted to CR status. Therefore, overall complete response rate was 92%. With median follow-up period of 30 months, 2-year progression-free and overall survival rate were 92%. No treatment related death or serious adverse event was found. Neutropenic fever was observed at 12 patients. Grade 3 or more serious adverse events were shown at 20 patients. However, no treatment-related death was found. Anemia and thrombocytopenia were common. Non-hematologic toxicities were relatively mild. Major non-hematologic toxicities were nausea, fatigue and peripheral neuropathy. Only one patient underwent salvage gastrectomy after starting RT due to pyloric obstruction caused by tumor deformity. This organ preserving combined treatment modality is highly effective and well tolerable for patients with localized gastric DLBL.