Comparative outcomes of oncologic therapy in gastric extranodal marginal zone (MALT) lymphoma: analysis of the SEER-Medicare database.
BACKGROUND
Therapy for gastric marginal zone (MALT) lymphoma is largely based on single-arm trials. This observational study compared survival with radiotherapy, rituximab and combination chemoimmunotherapy in this disease.


METHODS
Gastric MALT lymphoma cases diagnosed between 1997 and 2007 were selected from the Surveillance, Epidemiology and End Results-Medicare database. Propensity score analysis and competing risk models were used to compare survival in patients with stage IE treated with radiation or chemotherapy, and in patients of all stages treated with rituximab alone or with chemoimmunotherapy.


RESULTS
Among 1134 patients, 21% underwent radiation and 24% chemotherapy as initial treatment. In the balanced cohort of 347 patients with stage IE, radiotherapy alone was associated with a better cause-specific survival [hazard ratio (HR) 0.27, P < 0.001]. Patients receiving systemic therapy had better survival if it incorporated rituximab (HR 0.53, P = 0.017). After adjustment for confounding, the outcomes of those who received rituximab alone or combination chemoimmunotherapy were not statistically different (P = 0.14).


CONCLUSIONS
In elderly patients with stage IE gastric MALT lymphoma, radiotherapy was associated with lower risk of lymphoma-related death than chemotherapy. In those requiring systemic treatment, addition of cytotoxic chemotherapy to rituximab in the first-line regimen was not associated with improved survival.
The Cancer Center at Memorial Hospital of Rhode Island, Pawtucket, RI 02860, USA. adam_olszewski@brown.edu
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D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D058846:Antibodies, Monoclonal, Murine-Derived / Q000627:therapeutic use*; D000970:Antineoplastic Agents / Q000627:therapeutic use; D018906:Antineoplastic Agents, Alkylating / Q000627:therapeutic use; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000009:adverse effects / Q000627:therapeutic use; D003131:Combined Modality Therapy; D003520:Cyclophosphamide / Q000627:therapeutic use; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D018442:Lymphoma, B-Cell, Marginal Zone / Q000188:drug therapy* / Q000401:mortality / Q000532:radiotherapy*; D008297:Male; D006278:Medicare; D008875:Middle Aged; D012307:Risk Factors; D000069283:Rituximab; D018426:SEER Program; D015996:Survival Rate; D016896:Treatment Outcome; D014481:United States; D014740:Vidarabine / Q000031:analogs & derivatives / Q000627:therapeutic use
D058846:Antibodies, Monoclonal, Murine-Derived; D000970:Antineoplastic Agents; D018906:Antineoplastic Agents, Alkylating; D000069283:Rituximab; D003520:Cyclophosphamide; D014740:Vidarabine; C024352:fludarabine