Radiotherapy results in early stage low grade nodal non-Hodgkin's lymphoma

This is a retrospective review of stages I and II low grade nodal non-Hodgkin's lymphoma (NHL) seen at the Royal Marsden Hospital and treated with radiotherapy alone. From January 1970 to December 1989, 58 patients were treated. The Ann Arbor staging system was modified to subdivide stage II into localised and extensive disease, with localised disease representing no more than two contiguous regions. There were 40 stage I patients and 18 stage II patients (eight localised and 10 extensive). Volume of the radiotherapy was involved field only in 30 patients and extended fields in 28 patients. The median dose was 40 Gy in 20 fractions. The pattern of relapse was assessed as being systemic or within the standard volume. Survival and progression-free survival (PFS) were calculated. Prognostic variables of age, histology, stage and radiotherapy volume were analysed by multivariate analysis. The 5- and 10-year PFS for the total group were 59 and 43%, and corresponding OS figures were 93 and 79%. Age less than 60 years was a predictor of improved survival but not for PFS and we found no significance in histology, stage or extent of radiotherapy field for the other variables. All relapses occurred with disease outside the original volume, with three patients also relapsing in-field. Treatment of this disease produced an OS at 10 years of 79%. The plateau on the PFS plot suggested that some patients are cured. Young age was the only prognostic factor found for survival. Relapse is most frequently outside the treated volume. Our current treatment policy for stage I and II low grade NHL is involved field radiotherapy to a dose of 35 Gy in 20 fraction over 4 weeks.