The superior vena cava obstruction syndrome in bronchogenic carcinoma; pathologic physiology and therapeutic management.

Abstract

The onset of the superior vena cava obstruction syndrome in a patient with a bronchogenic carcinoma is an ominous event, heralding inoperability and producing severe discomfort and curtailment of useful activity. Unless decompression therapy is promptly and effectively instituted, the course is rapidly progressive, characterized throughout by distressing signs and symptoms. In our experience with a series of 38 such patients, roentgen therapy and/or nitrogen mustard5 have provided a striking degree of palliation and prolongation of useful activity in a majority of cases. The pathologic physiology and therapeutic management of this important complication deserve far more generous consideration than they have heretofore been afforded in the literature. Particularly is this so because of the rapidly rising incidence of bronchial cancer in recent years, the relative frequency of obstruction of the superior vena cava in the natural history of that disease, and the striking benefits of prompt treatment with x-rays and/or nitrogen mustard. In earlier communications (19, 20, 21), the authors reported on the use of nitrogen mustard as an adjunct to radiation in bronchogenic cancer, with therapeutic results in 40 patients, among them 9 with the superior vena cava obstruction syndrome. It is proposed, in the present paper, to discuss the pathologic physiology, clinical picture, radiographic features, and therapeutic management of this syndrome in the light of our broader experience. Pathologic Physiology The superior vena cava is the major trunk line for the return of venous blood to the right heart from the head, neck, upper extremities, and upper thorax (see Fig. 1A). This important channel is particularly vulnerable to obstruction by primary bronchial cancer or metastatic mediastinal nodes because (a) it is a thin-walled vessel with very low venous pressure, (b) it is locked in a tight compartment in the right anterior-superior mediastinum behind an unyielding sternum, (c) it is in intimate proximity to the right main bronchus, and (d) it is completely encircled by chains of highly important lymph nodes which drain all of the structures of the right thoracic cavity and the lower part of the left (5, 14, 22). In front of the superior vena cava lie the right anterior mediastinal or prevascular nodes. Behind it lurk the right lateral or paratracheal nodes, the lowermost and largest of which threatens the arch of the vena azygos, the great vein's most vital auxiliary (see Fig. 1B, C, D). Rouvière (22), Drinker (5), and McCort and Robbins (14) have recently added greatly to our knowledge of this important lymphatic drainage system in pulmonary cancer.