Outcome analysis for stage IE and IIE thyroid lymphoma

Previous reports have revealed modest results in the management of thyroid lymphoma with radiotherapy alone. This retrospective report evaluates the outcome of patients treated for thyroid lymphoma with radiotherapy alone and with combined modality therapy (chemotherapy and radiotherapy) at a single institution. Twenty-seven patients with stages IE and IIE non-Hodgkin's lymphoma of the thyroid gland were treated between 1960 and 1998 at Barnes-Jewish Hospital, of which 14 patients were stage IE and 13 patients were stage IIE. The median age at diagnosis was 67 years, and there were 21 females and 6 males evaluated. The median follow-up time was 38 months (range: 3-279 months). All patients had histologically proven non-Hodgkin's lymphoma, of which 22 patients (81%) were intermediate grade. Treatment consisted of radiotherapy alone in 19 patients and a combined modality therapy in 8 patients. The median radiation dose to the thyroid bed was 44 Gy, and most patients received a doxorubicin-containing regimen administered prior to radiotherapy. Patient, tumor, and treatment-related characteristics were evaluated using Cox regression analysis. Local-regional tumor control, disease-free survival (DFS), and overall survival (OS) were calculated using the Kaplan-Meier method. Four patients had local relapse in this series, with a crude local tumor control rate of 85%. No factor was determined to be significant for local tumor control. The actuarial 5-year DFS and OS for the entire cohort were 57%, and 56%, respectively. In terms of DFS, both age and stage were statistically significant. The 5-year actuarial DFS for patients less than age 65 years was 83% versus 37% for those more than this age (p = 0.024). Furthermore, the 5-year actuarial DFS for patients with stage I and II disease was 69% and 45%, respectively (p = 0.022). In multivariate analysis, age continued to be significant for DFS (p = 0.049). Overall survival analysis revealed age, local tumor control, and stage to be significant in univariate analysis. Multivariate analysis was further carried out using Cox proportional hazard model, and it revealed age (p = 0.006) and local tumor control (p = 0.007) to be significant. Primary thyroid gland lymphomas have a favorable outcome with appropriate therapy, but prognosis depends on both clinical stage and age at presentation. Because of the risk of both local-regional and distant failure, combined modality approaches that use chemotherapy with radiotherapy are warranted for intermediate- and high grade thyroid lymphoma.