Pulmonary marginal zone B-cell lymphoma of MALT type—What is a prognostic factor and which is the optimal treatment, operation, or chemotherapy?: Consortium for Improving Survival of Lymphoma (CISL) Study

Pulmonary marginal zone B-cell lymphoma of the MALT type (P-MZL) is a relatively rare form of lymphoma. We conducted a retrospective analysis of the clinical features and treatment outcomes of P-MZL for the evaluation of prognostic factors, and to collect information about the optimal treatment modality for this condition. From 1991 to 2008, a total of 61 patients with biopsy-confirmed P-MZL were retrospectively analyzed. The median age of our subjects was 60 (range, 34-79) years. Twenty-five of the patients (41%) were initially diagnosed without any symptoms. Video-assisted thoracic surgery was utilized for diagnosis in 19 patients (31%). Thirty-eight patients' conditions (62%) involved a single lobe. Lung lesions were bilateral in 15 patients (25%). Eleven patients evidenced synchronous involvement of extra-pulmonary site MZL. Overall, 56 of 61 patients were treated with surgery (n = 22), chemotherapy (n = 28), or radiotherapy (n = 6). Among them, 46 patients achieved complete or partial remission. The median time to progression (TTP) was 5.6 (95% CI, 2.6-8.6) years. Five patients died during follow-up. Extra-pulmonary MZL and LN involvement were shown to be poor prognostic factors for TTP. We noted no differences between the operation group and chemotherapy group in terms of TTP. P-MZL tends to be an indolent disease—characterized by prolonged survival with frequent relapses. This is similar to what is observed with other cases of MALT-type site MZL. In order to conserve lung function and reduce the risks of operation, chemotherapy should be considered as a first-line option for the treatment of P-MZL.