Low-grade mucosa-associated lymphoid tissue lymphoma: a retrospective analysis of 97 patients by the Hellenic Cooperative Oncology Group (HeCOG).

BACKGROUND: The aim was to examine characteristics and treatment results of patients with mucosa-associated lymphoid tissue (MALT) non-Hodgkin's lymphomas. PATIENTS AND METHODS: Epidemiological and clinical features of 97 patients with MALT lymphoma from the Hellenic Cooperative Oncology Group registry were analysed retrospectively for their prognostic significance in progression-free survival (PFS) and overall survival (OS). Comparisons were made between patients with gastric and nongastric sites of primary lymphoma and between different therapeutic modalities. RESULTS: Sixty-five patients presented with gastric and 32 with nongastric lymphomas. The most frequent locations of nongastric lymphomas were the bowel, lung and parotid. Gastric lymphomas occurred more frequently in males and younger patients compared with nongastric lymphomas. Seventy-four per cent of patients had early (Ann Arbor stages I-II) and 26% had advanced (stages III-IV) disease. The median PFS for the entire population was 44 months. At 5 years, 47% of patients were progression free and the OS rate was 80%. The most reliable prognostic factor for PFS and OS was the Ann Arbor stage; 5-year PFS was 67% versus 13% and 5-year OS 91% versus 51% for patients with early versus advanced disease, respectively (P < 0.001). Of the patients treated with chemotherapy only, 87% achieved an objective response and 71% complete response. Surgery did not offer survival benefit compared with chemotherapy in localised gastric lymphoma. CONCLUSION: MALT lymphomas represent a distinct disease entity with widespread extranodal origin, indolent clinical course and high chemosensitivity. Ann Arbor stage was the most reliable prognostic and predictive factor.