Roentgen Diagnosis of Intrathoracic Lymph-Node Metastases in Carcinoma of the Lung

It is recognized that in the combined surgical and radiologic attack upon cancer in any part of the body the cure rate will be influenced not only by the removal or destruction of the primary growth but by the absence or possible eradication of regional lymph-node metastases. When cancer develops in the lung, roentgenography is the only available method for preoperative determination of intrathoracic regional lymph-node involvement. It is therefore necessary that every effort be made toward the recognition of the presence or absence of such involvement at the time the primary tumor is discovered. The size of a lymph node increases with invasion by carcinoma as well as with the infection which may accompany it. When a group of enlarged intrathoracic nodes is encountered, the two etiologic factors can be separated in only certain instances. (Enlarged nodes associated with laryngeal or phrenic nerve paralysis are almost always metastatic.) When carcinoma is suspected and when enlarged intrathoracic lymph nodes are demonstrable roentgenographically, metastases should be considered present until proved to be absent. Conversely, the absence of enlarged nodes does not exclude the presence of a small tumor embolus. Because this knowledge is important for a correct surgical attack upon the tumor, an attempt to recognize and describe the roentgen appearance of the intrathoracic lymph nodes has been made. The results of the study form the basis of this report. For the purposes of the investigation, 221 cases of proved carcinoma of the lung treated surgically during the years 1942 through 1949 were reviewed. According to the surgeon's operative notes, 66 percent (146 cases) showed enlargement of regional lymph nodes. In 11 of these cases the pathologist found no tumor in the submitted nodes; in 135 carcinoma was present. Further analysis was carried out in the latter group, plus 16 additional cases operated on in 1950. Of the total 151 cases, 48 were excluded, 3 because the tumor was multicentric, 34 because of inadequate data, and 11 because of insufficient surgical or pathologic information. Of necessity, the 103 cases finally selected were chosen on the grounds of the roentgen, surgical, and pathologic material at hand. Any case in which roentgenograms were unavailable or were technically inadequate was excluded, as were those in which the surgical exploration of the mediastinum was incomplete or was described with insufficient detail to allow estimation of the degree or localization of the lymph-node involvement. In 53 of the group the primary tumor as well as the metastatic foci were removed and were studied histologically; in the remaining 50 the extent of the tumor precluded surgical removal. In the latter cases the surgeon noted the lymphatic involvement and at least one of the nodes was removed for microscopic examination.