Hodgkin's disease: a reassessment of prognostic factors following modification of radiotherapy

Between 1970 and 1982, 175 patients with Stage IA, B, IIA, B, or IIIA Hodgkin's disease were treated with curative radiotherapy following surgical staging. The patients treated prior to 1975 received either regular extended or total nodal field treatments (Treatment Group 1, N = 65). Unsatisfactory results from this treatment program led to treatment modification in 1975. The modified protocols consisted of low-dose lung irradiation in patients having large mediastinal masses and/or hilar disease, and low-dose liver irradiation for Stage IIIAS+ patients (Treatment Group 2, N = 110). Recurrence-free survival rates improved significantly for various risk groups. Univariate analysis indicated that age, stage, symptoms, mediastinal mass size, number of sites involved, hilar disease, stage, and symptoms were significant risk factors in Treatment Group 1. In Treatment Group 2, only sex was a statistically significant risk factor. Stepwise Cox regression analysis for risk factors selected mediastinal mass size and stage as the most significant prognostic factors in Treatment Group 1. In Treatment Group 2, number of initial disease sites and sex were the most significant risk factors. The results of the study show significant improvement in recurrence-free survival rates in Treatment Group 2. It is concluded that these improvements are due to the modification in treatment.