Long-Term Outcomes of 107 Cases of Primary Thyroid Mucosa-Associated Lymphoid Tissue Lymphoma at a Single Medical Institution in Japan

Context: Thyroid mucosa-associated lymphoid tissue (MALT) lymphoma is a type of extranodal lymphoma with a favorable prognosis. Objective: To provide information on long-term outcomes that would facilitate establishment of the optimal management strategy for thyroid lymphoma. Design, Setting, and Participants: Medical records of 107 patients (median age 67 years, 20 males, 87 females) who were diagnosed with localized thyroid MALT lymphoma stage IE or IIE at Ito Hospital were retrospectively reviewed. Main Outcome Measure: Overall and event-free survival (EFS). Results: Initial treatments included radiation therapy (RT) alone (n = 58), combined modality therapy (CMT) (n = 48), or chemotherapy alone (n = 1). All 107 patients responded to the treatment, six of whom experienced relapse. Only one patient died of lymphoma. The 5-year overall survival (OS) and EFS rates were 94% [95% confidence interval (CI), 87% to 97%] and 92% (95% CI, 85% to 95%), respectively, and the 10-year OS and EFS rates were 91% (95% CI, 83% to 95%) and 84% (95% CI, 74% to 90%), respectively. Of the 106 patients with information available on adverse events, 71 patients (67%) developed hypothyroidism after primary thyroid lymphoma treatment. The CMT group showed additional chemotherapy-induced adverse reactions in the form of neutropenia, neuropathy, constipation, and pneumonia. The 5-year OS rates of patients treated with CMT and RT were 93% (95% CI, 81% to 98%) and 94% (95% CI, 84% to 98%), respectively. Conclusions: Long-term outcomes of localized thyroid MALT lymphoma are favorable with all initial treatment modalities.