Long-term results of low dose total body irradiation for advanced non-Hodgkin lymphoma.

Sixty-eight patients received fractionated low dose total body irradiation (LTBI) as treatment for non-Hodgkin lymphoma (NHL) at the Rotterdamsch Radio-Therapeutisch Instituut (RRTI) in the period 1973-1979. Ninety percent (61/68) of these patients had advanced disease (Stage III + IV). According to current malignancy grade classifications, 34 patients had low grade NHL, 10 intermediate, and 19 high grade. In 5 cases no exact grading was possible. LTBI was given 3 times a week, midline dose 0.1 Gy, using 6 or 25 MeV photons to a mean total dose of 1.78 Gy. Initial response rate for low, intermediate, and high grade NHL was resp. 84, 42, and 40%. The main prognostic factor for survival and recurrence-free survival (RFS) was malignancy grade. Probability of uncorrected survival at 10 years for low, intermediate, and high grade was resp. 34, 0 and 0%. Probability of RFS at 10 years was resp. 19, 0, and 0%. Neither stage nor sex had any influence on survival. Age was reversely correlated with survival, but was not correlated with RFS. Influence of prior therapy (18 patients) on survival and RFS was separately analyzed. Neither survival nor RFS of unfavorable histologic type NHL (high and intermediate grade) was influenced. On the other hand patients with a favorable histologic type NHL (low grade) had a significantly (p less than 0.05) better RFS if they received LTBI as initial treatment, but survival was not significantly influenced. RFS at 5 and 10 years of patients who received LTBI as first treatment was respectively 32% and 27%. No treatment related complications were noted. Subsequent chemotherapy in case of relapse was not hampered by previous LTBI. The high response rate and extended RFS, without maintenance therapy, makes LTBI a preferable first line treatment for patients with advanced stage low grade NHL.