Mediastinoscopy and mediastinal roentgenology. A clinical correlation

Mediastinal staging in non-small-cell lung cancer

Decision analysis was used to study the approach to staging mediastinal involvement in patients with non-small-cell lung cancer (NSCLC). Various diagnostic strategies for mediastinal disease staging using computed tomography (CT), mediastinoscopy, and bronchoscopy with transbronchial needle aspiration (TBNA), either individually or in series, were compared and found to result in similar patient life expectancies. Two strategies, one using bronchoscopy and TBNA alone and the other using it in combination with CT, were consistently least expensive across a wide range of prior probabilities, test characteristics, and charges. The authors conclude that strategies for staging mediastinal involvement in NSCLC that rely on bronchoscopy and TBNA are preferable because they are least expensive.

The prognostic significance of preoperative assessment of mediastinal lymph nodes in patients with lung cancer

In order to evaluate the prognostic significance of the preoperative assessment of mediastinal lymph nodes, 100 patients with potentially operable lung cancer underwent two-plane tomography, computed tomography (CT), transbronchial needle aspiration (TBNA; 47 patients), and cervical mediastinoscopy. Mediastinoscopy proved to be the most accurate staging procedure. Tomography was less specific, detecting only advanced mediastinal node involvement, and CT was as sensitive as mediastinoscopy but sensibly less specific. TBNA gave no false positive results but a false negative rate of 25.5 percent. Accurate preoperative staging of mediastinal nodes is mandatory to optimize the resectability rate of lung cancer. Where metastatic involvement of mediastinal nodes was preoperatively documented at more than one level, tumors were invariably unresectable. Mediastinoscopic demonstration of intracapsular metastases at only one level did not preclude complete resection. Before thoracotomy, confirmation of neoplastic spread to mediastinal nodes suggests very low survival rates, especially in patients with incomplete removal of tumors.

Mediastinal assessment for staging and treatment of carcinoma of the lung

Invasive diagnostic procedures for mediastinal assessment, such as mediastinoscopy, are necessitated by the importance of staging lung cancers, both to plan the treatment and to estimate the prognosis. Other noninvasive techniques may complement or be substituted for mediastinoscopy under certain specific clinical settings. Thus with the introduction of newer diagnostic technologies, such as computed axial tomography, the strategy for mediastinal assessment should be continually reevaluated. In this review, the diagnostic sensitivity, specificity, and overall accuracy of various techniques reported in the literature are examined to elucidate their current roles in assessing the mediastinal involvement in patients with lung cancer.

The value of computed tomography in staging bronchogenic carcinoma: a changing role for mediastinoscopy

Forty-one patients underwent operative staging for bronchogenic carcinoma following computed tomography of the mediastinum between August, 1982, and March, 1984. Twenty-seven patients were classified as Stage I preoperatively; in 2 of them, positive mediastinal nodes were found at thoracotomy. For the 14 patients in whom positive nodes had been identified by computed tomographic (CT) scanning, staging was unchanged as a result of the findings at mediastinoscopy or thoracotomy or both. In this series, computed tomography had a sensitivity of 89%, a specificity of 100%, and an overall accuracy rate of 95%. We conclude that mediastinoscopy is not needed in patients without evidence of mediastinal nodal enlargement by CT scan; when performed, it should be guided toward those nodes identified as positive.

Accuracy of chest computerized tomography in detecting malignant hilar and mediastinal involvement by squamous cell carcinoma of the lung

The accuracy of chest computerized tomography (CT) in detecting malignant hilar and mediastinal involvement by squamous cell carcinoma of the lung is examined. The preoperative chest CT scans of 74 patients with pathologically proven squamous cell lung carcinoma were prospectively and retrospectively reviewed. Criteria for the diagnosis of malignant hilar involvement were nonvascular mass enlarging the hilum; local alteration of hilar contour; adenopathy greater than 1 cm; thickened posterior wall of the bronchus intermedius and distal upper lobe bronchi; and bronchial displacement, compression, and obstruction. Criteria for the diagnosis of malignant mediastinal involvement were confluence of tumor with the mediastinum, altered contour of the azygoesophageal recess, thickened posterior wall of the proximal main stem bronchi, and mediastinal adenopathy greater than 1 cm. Calcified hilar and mediastinal nodes were considered benign. Our results, corrected for reader error, were 92% sensitive, 92% specific, and 96% accurate in the hilum and 95% sensitive, 77% specific, and 82% accurate in the mediastinum. These data support a significant role for chest CT in the preoperative staging of non small cell lung carcinoma.

Sensitivity of chest radiography, computed tomography, and gallium scanning to metastasis of lung carcinoma

To determine the efficacy of radiologic techniques in preoperative staging of the mediastinum for lung carcinoma, the authors studied 45 patients with chest films supplemented with oblique views, esophagrams, gallium scans, and computed tomograms (CT). They interpreted the studies and correlated surgical findings using a modified classification of lymph node regions. The mediastinum was positive on chest films in 14 of the 21 cases with pathologically proved mediastinal metastases (33% false-negative). Gallium scans in cases with a positive primary were positive in 12 of 15 cases with mediastinal or hilar metastases (20% false-negative). Computed tomography showed nodes over 1 or 1.5 cm in size in or adjacent to the biopsy-positive node region in 18 of 19 patients (5% false-negative), extranodal mediastinal involvement, and 9 of 10 proven hilar metastases. Computed tomography is a sensitive screening technique in patients who would otherwise require an invasive staging procedure, but is not highly specific (false-positive rate 38%).

The role of gallium-67 in the clinical evaluation of cancer

This review is based primarily on historic data, and it examines the indications for and limitations of gallium-67 scanning in the evaluation of patients with neoplasms. The use of gallium-67 scans is discussed according to tumor type, and data from the most representative and comprehensive studies are included. The results described, some of which were obtained primarily with older imaging techniques, should be regarded as representing the minimum that can be expected from application of this imaging procedure.

Oblique hilar tomography and mediastinoscopy. A correlative prospective study in 100 patients with bronchogenic carcinoma

One hundred patients with bronchogenic carcinoma had oblique hilar tomography preoperatively to evaluate the pulmonary hila. Subsequently, all of these patients underwent mediastinoscopy or thoracotomy or both. Hilar and mediastinal nodes were evaluated for the presence of metastasis. These findings were then correlated with the radiographic findings of oblique hilar tomography. We found oblique hilar tomography to be a useful method of selecting patients for mediastinoscopy. The negative predictive value of oblique hilar tomography for mediastinal involvement was 95 percent, while the positive predictive value was 75 percent. Thus, patients with negative findings on oblique hilar tomography need not undergo mediastinoscopic examination prior to thoracotomy.

Evaluation of tomography and mediastinoscopy for the detection of mediastinal lymph node metastases

In a prospective study of 88 patients seen consecutively with proven or suspected bronchial carcinoma, the validity of x-ray tomography and routine mediastinoscopy was tested for the detection and evaluation of mediastinal lymph node metastases. Positive mediastinum was defined as malignant tissue found in the mediastinum and negative mediastinum as mediastinoscopy with negative results plus a negative intraoperative mediastinal lymph node dissection. Thirty-four patients were eliminated from the analysis because carcinoma was not found or because mediastinal evaluation was incomplete by these criteria. Twenty-eight of the remaining 54 patients had mediastinal metastases. Sensitivity was 67% for tomography and 79% for mediastinoscopy. Specificity was 92% for tomography and 100% for mediastinoscopy. The differences were not significant. Sixty-six of 85 mediastinoscopies were unnecessary or unhelpful in the decision to exclude a patient from surgical intervention. Among 19 patients with lesions presumed to be inoperable based on results of mediastinoscopy (i.e., perinodal metastatic growth suspected by palpation or histologically proven), 14 patients had positive tomographic scans and 1 could not be evaluated radiographically because of right upper lobe atelectasis. We conclude that tomography of the upper mediastinum should be used to select patients for mediastinoscopy.

Pre-operative mediastinal evaluation in primary bronchial carcinoma--a review of staging investigations

A review of staging investigations in the preoperative evaluation of mediastinal involvement in primary bronchial carcinoma is presented. The following conclusions are offered as guidelines for the use of mediastinal staging procedures in clinical practice: Surgical staging methods have the over-riding advantage of superior specificity over indirect imaging techniques. Where 67Ga-imaging or CT scanning are not available, routine pre-operative mediastinoscopy or, when appropriate, mediastinotomy will identify most patients with non-resectable disease but this approach entails a high proportion of true negative examinations. Radioisotope ventilation and perfusion lung imaging has no place in the pre-operative staging of lung cancer. Where the techniques are available, 67Ga-imaging and CT scanning have a use in selecting patients for mediastinal exploration. A negative mediastinal 67Ga scan or a negative CT examination suggest that mediastinal exploration will be unrewarding in the vast majority of cases and may be omitted prior to thoracotomy. A positive mediastinal 67Ga scan or the demonstration of abnormal mediastinal nodes by CT is an indication for mediastinal exploration which, if negative should be followed by thoracotomy.

Computed tomography in lung cancer

Computed-assisted tomography produces a cross-sectional image of the body using x-ray absorption measurements. Density differences are much more apparent than on conventional radiographs, although spatial resolution is not so fine. Lung cancer, can be evaluated accurately with regard to size, location, and whether regional or mediastinal lymph nodes are enlarged. Although enlarged granulomatous nodes generally tend to be dense, histologic specificity is not available. Computed tomography is recommended as a screening technique in lung cancer staging for patients whose routine radiographs are normal but whose primary lesions fulfill criteria for mediastinoscopy. If findings on computed tomography are normal, thoracotomy should then be performed; if enlarged nodes are detected, then a biopsy is needed to exclude operability. This strategy presumes that computed tomography has high sensitivity, although it remains to be proven by further experience whether the false-negative rate of computed tomography is an acceptable 10 to 15 percent. Computed tomography has been shown to be of considerable value in optimizing radiation therapy of lung cancer, and in diagnosing pleural complications of the cancer or its treatment.

Preferred surgical treatment for alveolar cell carcinoma

An analysis of our experience with 48 patients having bronchiolar or alveolar cell carcinoma is reported. The remarkable biological variability of this peripheral tumor has important surgical implications. Basically, two dominant clinical presentations occur. In the less common diffuse or multinodular form, prolonged survival is infrequent regardless of the therapeutic approach. Often these patients die from respiratory compromise due to the tumor itself. In the more common localized or solitary form the prognosis for cure is good, approximating 47% or higher. Based on the material presented, lobectomy is the preferred method of surgical treatment. In patients manifesting multinodular disease, surgical resection rarely seems warranted. The concept of preserving pulmonary tissue is stressed.