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.