PRIMARY EXTRANODAL MARGINAL ZONE LYMPHOMA of the LUNG (BALT-LYMPHOMA): Results of a Retrospective Analysis on Behalf of IELSG

Abstract 1770

Bronchial-associated lymphoid tissue (BALT) lymphoma is a distinct subgroup of low grade B-cell extranodal lymphoma. The limited clinical information available in the literature makes it difficult to understand if such an indolent lymphoma may have a clinical outcome different from that observed in other extranodal marginal zone lymphomas. The aim of this study is to collect and analyze clinical characteristics of patients with primary marginal zone malignant lymphoma of the lung principally focusing on diagnosis, treatment modality, outcome and finally to evaluate biological and molecular features which may correlate with clinical behaviour.

We collected clinical information and histological material on 73 patients diagnosed with marginal zone lymphoma of the lung from February 1990 to August 2008. Central pathology reviewed all histopathological material and the diagnosis was confirmed in 64 (88%) patients. The retrospective analysis has been conducted on this subset of patients. The majority of them (58/64) had limited disease at diagnosis with a good performance status (0-1) and low prognostic index (IPI 0–2). FISH analysis showed a rearrangement on 18q21 in 12 of cases. Median time from diagnosis to any treatment was 30 days (range 0–773). Twenty patients received only local treatment including definitive surgery or radiotherapy. 52 patients needed additional systemic treatment because of advanced stage or incomplete surgical resection. Most of them (26) received an alkylating containing regimen while only 10 patients were treated with an anthracycline containing regimen and 16/52 received monoclonal antibody in combination with chemotherapy. With a median follow up of 54 months, 17/64 patients (27%) relapsed. The median time to relapse was 28 months (range 1–82). No difference in terms of PFS or OS was observed among patients receiving systemic anthracycline or alkylating containing regimens. No significant correlation with MALT 1 aberrations was found.

Clinical results observed in such retrospective study seem to suggest as surgery clearly benefits patients with localized disease. Chemotherapy can be reserved for early aggressive relapse. Systemic treatment could be recommended for patients with advanced stage or with incomplete response after the surgical procedure: when chemotherapy must be considered, alkylating containing regimens seem the best option. Considering data of a “pre-rituximab era”, the role of monoclonal antibodies still needs to be clarified and ongoing trials from IELSG could be helpful on this topic.