Role of radiation therapy in the management of primary mediastinal large B-cell lymphoma (PMLBL)

PURPOSE: PMLBL is a rare disease in Japan, and its optimal management and prognosis remain to be examined. A retrospective analysis of combined modality treatment in PMLBL was performed. MATERIALS AND METHODS: Three women and four men (mean age, 36 years) were found to have PMLBL. Six patients had stage II disease, and one patient stage III disease. Each patient had a mediastinal tumor over 9 cm in diameter. The numbers of risk factors according to the international prognostic index (IPI) and modified tumor score (mTS) were 2 and 2 or 3, respectively. All patients were treated by doxorubicin-based chemotherapy. Two patients underwent tumor resection. Radiation therapy of 27.3 to 40 Gy (mean, 32 Gy) was delivered, after chemotherapy in six patients, and before chemotherapy in one. RESULTS: Only one stage IIE patient recurred in the bilateral kidneys and had a fatal outcome. The remaining six patients remain disease-free at follow-up ranging from seven to 126 months. Positive accumulation of gallium scintigraphy after chemotherapy was converted to negative by radiation therapy. CONCLUSIONS: The favorable prognosis of PMLBL was confirmed in this study. Radiation therapy should preferably be delivered to all patients with PMLBL after chemotherapy.