Outcome of patients with non-Hodgkin's lymphoma of the stomach after gastrectomy: clinicopathologic study and reclassification according to the revised European-American lymphoma classification.

Abstract

The best treatment for patients with non-Hodgkin's lymphoma (NHL) of the stomach is still uncertain. The revised European-American lymphoma (REAL) classification has helped to define new, potentially more appropriate classification schemes for gastric lymphomas. Fifty-one resected gastric lymphomas were reclassified according to the REAL classification, and the efficacy of multimodal treatment was examined retrospectively. The principal treatment plan consisted of: (1) surgical resection of the stomach with lymph node dissection, followed by (2) systemic chemotherapy, mainly using the cyclophosphamide/doxorubicin/vincristine/prednisone (CHOP) regimen. According to the Ann Arbor classification, 27 patients had stage IE, 19 had stage IIE, and 5 had stage IV NHL. Using the REAL classification, we diagnosed diffuse large B-cell lymphoma (DLBL) in 23 patients, marginal zone B-cell (low-grade mucosa-associated lymphoid tissue [MALT]-type) lymphoma in 22, follicle center lymphoma in 4, mantle cell lymphoma in 1, and peripheral T-cell lymphoma in 1 patient. Nine of the 51 patients relapsed, and 8 patients with DLBL died of cancer. Survival rates at 5 years after surgery were 96.0% for stage IE, 83.3% for stage IIE, and 87.0% for all patients. Univariate analysis indicated that the tumor histology (according to the REAL classification), depth of invasion, degree of nodal involvement, Ann Arbor staging, and chemotherapy had an impact on patient outcome (P = 0.0018; P = 0.0002; P = 0.0308; P = 0.0016, and P = 0.0118, respectively). These data reveal that gastric NHL, especially of the low-grade MALT-type, often remains localized and has a good prognosis after surgery. The REAL classification was useful for classifying new categories of NHL, including the MALT-type, in the clinical setting, and for determining the optimal treatment modality for gastric NHL.