Thyroid lymphoma. The case for combined modality therapy.

Abstract

Radiation therapy with or without surgery is generally considered standard treatment for lymphoma of the thyroid. Because of the small number of cases, the role of chemotherapy or combined modality treatment is difficult to determine. The published literature was analyzed, supplemented by a series from Yale, for the incidence of local and distant relapse after radiation therapy, chemotherapy, or combined modality treatment for Stage I-II thyroid lymphoma. Patients with advanced disease or in whom radiation was probably inadequate were excluded. Only patients receiving an anthracyline-based regimen were considered in the group with chemotherapy. Patients receiving single agents or non-anthracycline-based regimens were excluded from analysis or, if they also received radiation, were included in the group that received radiation only. Including a series from Yale, a total of 211 patients with Stage IE and IIE thyroid lymphoma were identified. Distant and overall relapse rate were significantly lower in the group that received combined modality treatment. Local relapse was also less, but the difference was not statistically significant. In a small number of patients with disease confined to the neck, the results with radiation were similar to combined modality treatment if the mediastinum was included in the treatment port. Although mucosa-associated lymphoma tissue lymphomas are thought to have a low distant recurrence rate and are therefore often treated with local therapy alone, a review of the published literature suggests that 30% of thyroid lymphomas with clinically localized disease will have a distant relapse. The addition of chemotherapy to radiation significantly lowered distant and overall recurrence.