SOHO State of the Art Updates and Next Questions: Treatment Options for Marginal Zone Lymphoma

Current classifications identify 3 primary types of marginal zone lymphoma (MZL): extra nodal, splenic, and nodal MZL. MZLs typically have excellent long-term outcomes and often do not require immediate treatment. For asymptomatic patients, active surveillance (watch-and-wait) is the standard approach. However, exceptions exist. Asymptomatic patients with Helicobacter pylori-positive gastric MZL should receive antibiotic eradication therapy upon diagnosis. Similarly, asymptomatic patients infected with hepatitis C virus (HCV) should receive antiviral therapy. Surgical resection is generally not indicated. Involved-site radiotherapy (ISRT) is recommended for localized disease (20-24Gy, depending on the anatomical site). While higher doses are often needed for curative intent, very low-dose ISRT (2×2 Gy) can achieve long-term control and provide effective palliation with minimal toxicity when a definitive cure is not the goal. Symptomatic patients with advanced-stage disease may benefit from systemic rituximab-based treatment. Rituximab monotherapy is suitable for patients who cannot tolerate chemotherapy or prioritize a low-toxicity initial approach. The combination of rituximab with bendamustine or chlorambucil can result in longer response duration and progression-free survival, but not in improved overall survival, and may be preferred for severely symptomatic patients with advanced disease. More intensive doxorubicin-containing regimens, which are more toxic, should be reserved for patients with histological transformation, aggressive presentations, or bulky masses. Although data from clinical trials are limited, several new therapies have shown encouraging results, including bispecific antibodies, chimeric antigen receptor (CAR)-T cell therapy, and small molecules. Treatment choices depend on the MZL subtype, stage, age, comorbidities, and therapeutic goals.