Localized non-Hodgkin lymphoma involving the thyroid gland

BACKGROUND: The current study was undertaken to define the natural history and patterns of failure of localized non-Hodgkin lymphoma (NHL) involving the thyroid gland. METHODS: A retrospective review of 51 patients with Ann Arbor Stage I or II NHL involving the thyroid gland was performed. The median age of the patients was 59 years. There were 33 females. There were 21 patients with Stage I disease and 30 patients with Stage II disease. The International Prognostic Index (IPI) was known for 43 patients (it was 0 in 16 patients and > or = 1 in 27 patients). Fifteen patients had mediastinal involvement. Four patients underwent thyroidectomy, 18 patients received radiation therapy, 5 patients received chemotherapy, and 24 patients received combined modality therapy (CMT) with chemotherapy and radiation therapy. Treatment modality, patient gender, IPI, disease stage, and mediastinal involvement were examined for significance with regard to overall survival (OS) and failure free survival (FFS). RESULTS: The 5-year OS and FFS rates were 64% and 76%, respectively. The 5-year FFS rates by treatment regimen were 76% for radiation therapy, 50% for chemotherapy, and 91% for CMT (P = 0.15). IPI was found to be the only significant predictor of OS. The 5-year OS rates were 86% and 50%, respectively, for IPIs of 0 and > or = 1 (P = 0.02). None of the 5 variables were found to correlate significantly with FFS, although the 5-year FFS rates were 93% and 68%, respectively, for IPIs of 0 and > or = 1 (P = 0.08). Eleven patients failed treatment. Nine patients had a component of distant failure across the diaphragm. CONCLUSIONS: The prognosis of patients with localized NHL involving the thyroid gland appears to be very good, especially when CMT is used. Distant recurrences appear to account for the majority of treatment failures. The IPI was found to be a significant prognostic factor for OS and a marginal one for FFS.