Treatment outcomes in patients with extranodal marginal zone B-cell lymphoma of the lung.

Objectives: To evaluate clinical presentations, treatment modalities, and outcomes of pulmonary mucosa-associated lymphoid tissue (MALT) lymphoma by stage strata.

Methods: We retrospectively reviewed 51 patients diagnosed with pulmonary MALT lymphoma between January 2003 and December 2015. To compare treatment modalities and outcomes, we stratified the patients into low-stage (IE/IIE) and high-stage (IIIE/IVE) groups using modified Ann Arbor staging. Progression-free survival was estimated using Kaplan-Meier curves, and differences were compared using the log-rank test. A hazard ratio of progression by stage strata, adjusted for other clinical variables, was determined using a Cox adjusted proportional hazards model.

Results: The majority of patients had stage IE disease (76.5%; 39 of 51). With advancing stage, patients were more likely to have respiratory and B symptoms and higher International Prognostic Index scores. The most common treatment modality was surgical resection in low-stage patients (33 of 43) and chemotherapy in high-stage patients (7 of 8). At a median follow-up of 40.7 months, progression-free survival was longer for low-stage patients (median, 40.7 months vs 24.9 months; P < .001), and high-stage patients were 9.2 times more likely to progress (hazard ratio, 9.24; 95% confidence interval, 1.93-44.36). Among 30 patients with surgically resected stage IE disease, 8 with central lesions were treated via lobectomy and 22 with peripheral lesions were treated via lobectomy (n = 8) or limited resection (n = 14). One of these patients, with a central lesion, experienced disease recurrence.

Conclusions: Our findings suggest that the clinical course of low-stage pulmonary MALT lymphoma, for which the mainstay of treatment is surgical resection, might be indolent.