The question of whether prophylactic irradiation of surrounding uninvolved sites will yield better results than localized irradiation alone in the management of Hodgkin's disease is presently unsettled. Peters (13) in 1950 and later, in 1958, Peters and Middlemiss (15) reported that prophylactic irradiation of all proximal lymph node chains in addition to the sites of clinical involvement increased the longevity of patients with localized Hodgkin's disease when they were compared to those who were given local irradiation only. This concept of prophylactic irradiation was based on the clinical impression that, before they became generalized, recurrences were more frequent in contiguous lymph node chains than at distant sites. In 1962, Kaplan (9) confirmed the belief that radical irradiation (local plus prophylactic) yielded a result superior to that of palliative local irradiation in respect to freedom from recurrences. The report which challenged this approach of prophylactic irradiation was that of Easson and Russell (4) in 1963. Their experience of a 40 per cent fifteen-year survival rate in a large series of patients treated by adequate dosage to localized fields resulted in figures comparable to those of Peters (13) with extended-field irradiation. Scheer, in 1963, felt that the prompt treatment of proximal recurrences in patients with Stage I Hodgkin's disease was sufficient to produce long-term survivors and that the seemingly random distribution of the subsequent sites of involvement provided little basis for the selection of fruitful areas to treat prophylactically. An analysis of our experience in which the two technics of treatment (localized vs. extended fields) were employed, indicates that the problem remains unsolved. Present Clinical Series The total group of patients with Hodgkin's disease treated at the University of Rochester Medical Center's Division of Radiotherapy between 1930 and April 1964 consists of 113. All cases were histologically verified. The present study is limited to 39 cases of localized Hodgkin's disease, Stages I and IIA, treated by two different therapeutic policies (Fig. 1). A. Local Irradiation Group Before 1958, 18 patients with Stages I and IIA Hodgkin's disease were treated by local irradiation to the entire involved lymph node region, employing generous single- or multiple-field arrangements. The major aim of treatment was to assure local tumor regression; once this was achieved, irradiation was terminated. The tumor doses ranged from 600 to 3,400 R with half the patients receiving 1,500 R or less and the majority less than 2,000 R. The quality of radiation varied from 220 kV to 1 MeV. B. Prophylactic (Extended-Field) Group From 1958 to 1963, 21 patients with similar staging were treated by a technic based on the principles of Vera Peters (13) in which the surrounding clinically uninvolved lymph-node-bearing sites were treated.