The major impetus for the development of new techniques of treatment is the failure of an existing technique. In the early sixties, the introduction of pedal lymphangiography to exclude infradiaphragmatic nodes promised precise definition of localized stage I and II Hodgkin's disease. The use of megavoltage irradiation through a shaped mantle field to treat the nodal disease and adjacent sites above the diaphragm promised cure, since adequate tumoricidal doses could be delivered. The "mantle technique" controlled approximately 50% to 60% of all such patients, as documented in numerous series.58 The pattern of failure was consistent; the vast majority of patients had a transdiaphragmatic extension of disease, most often involving the para-aortic lymph nodes or the spleen.
The transdiaphragmatic extension to the para-aortic lymph node region has been a central focus of discussion. Its subsequent appearance despite negative lymphangiograms has led to speculations about its development. The most controverted concept