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

Computed Tomography and Mediastinoscopy in the Assessment of Resectability of Lung Cancer

In order to assess the potential of computed tomography (CT) of the mediastinum and mediastinoscopy in the staging of lung cancer, 125 patients were examined. Of these, 104 underwent thoracotomy, at which there was no evidence of mediastinal tumour involvement in 79 while 25 patients had signs of tumour spread. The sensitivity and specificity of CT were 87.0 per cent and 95.8 per cent, respectively, in the detection of direct tumour extension with a mediastinal mass. When lymph node enlargement was the sole finding, CT did not provide any differentiation between benign and malignant lymphadenopathy. The mediastinal involvement was inaccessible on mediastinoscopy in 18 cases (72%). Despite the surperior sensitivity of CT it was often difficult to determine whether direct tumour infiltratin of mediastinal structures had occurred. It was concluded that CT is necessary for screening the entire mediastinum and, when it reveals no evidence of mediastinal tumour spread, mediastinoscopy will yield no further information. Mediastinoscopy will help to correctly identify accessible mediastinal lymph node involvement of the superior mediastinum and to define the mediastinal tumour invasion in doubtful cases.

Video-assisted mediastinoscopy: experience from 240 consecutive cases

BACKGROUND

We report our experience with video-assisted mediastinoscopy.

METHODS

We retrospectively reviewed clinical records of all patients who underwent video-assisted mediastinoscopy in a 26-month period. Video-assisted mediastinoscopy was performed in the presence of enlarged lymph nodes (short axis > 1 cm) found at computed tomography scan. Data about operative time, node stations sampled, number of biopsies, and operative complications were collected. Results of the pathologic examination were recorded, as well as (when different) the definitive diagnosis.

RESULTS

Video-assisted mediastinoscopy was performed in 240 consecutive patients. In 2 patients, the technique was employed for resection of a mesothelial cyst. In the other cases, it was used for diagnosis of enlarged nodes or staging of lung cancer. Mean number of biopsies was 6.0; mean number of sampled nodal stations was 2.3. Mean operative time was 36.6 minutes. Two operative complications occurred: a pneumothorax not requiring drainage and an injury to the innominate artery requiring manubrial split and suture. In 192 patients, the definitive diagnosis was lung cancer (18 small-cell lung cancers). In the remaining 46 patients, video-assisted mediastinoscopy allowed establishment of the diagnosis (sarcoidosis, n = 22; reactive hyperplastic lympho-adenitis, n = 13; tuberculosis, n = 4; involvement by malignancies other than lung cancer, n = 7). Among the 174 patients with non-small cell lung cancer, mediastinal nodal involvement was recognized in 107 cases (N3, n = 28; N2, n = 79). Sixty-seven patients were staged N less than 2; 47 underwent thoracotomy. Postthoracotomy staging agreed with video-assisted mediastinoscopy staging in 44 cases (93.6%).

CONCLUSIONS

Video-assisted mediastinoscopy proved to be safe and effective in nodal assessment of the mediastinum.

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.

Efficacy and benefit of mediastinal computed tomography as a selection method for mediastinoscopy

In 95 consecutive patients with proven or suspected bronchial carcinoma, computed tomographic evaluation of the upper mediastinum for N2 disease was performed prospectively. Patients with positive results underwent mediastinoscopy. Patients with perinodal N2 or N3 disease at mediastinoscopy were not considered candidates for operation. The mediastinum was declared negative only when intraoperative mediastinal lymph node dissection showed tumor-free nodes. Of the 95 patients, 12 had benign lesions, 14 were excluded from further evaluation because the lymph node status of the mediastinum was not proven intraoperatively, and 6 others were excluded from the final evaluation because of violation of the protocol. Twenty-two of the 75 remaining patients had a positive computed tomographic scan and underwent mediastinoscopy. Fourteen patients with positive results were considered to have inoperable disease. Fifty-three patients (70.7%) did not undergo mediastinoscopy. We performed seven probably incomplete resections, two for palliative reasons, and two thoracotomies without resection in patients with N2 disease. A policy of routine mediastinoscopy would have prevented only 5% of the thoracotomies performed in patients with lung cancer.

Complications of mediastinoscopy

From 1968 to 1987, mediastinoscopy was performed on 2021 consecutive patients. The procedure was carried out in 35.7 per cent on patients with a pulmonary infiltrate and in 28.8 per cent with bronchogenic carcinoma. Mediastinoscopy was positive in 54 per cent of the cases. The total number of complications was 2.3 per cent (47/2021). There were four cases with major haemorrhage, three tracheal ruptures and three wound infections. Recurrent nerve paralysis was verified in three patients and pericardial rupture in two patients. The total of major complications was 0.5 per cent (10/2021). There was no deaths in this series. In the authors' opinion, mediastinoscopy can be regarded as an effective and safe procedure in the hands of an experienced surgeon.

Mediastinoscopy in the investigation of primary mediastinal lymphadenopathy

Mediastinoscopy was introduced by Carlens (1) in 1959 to obtain lymph node biopsies from the superior mediastinum in patients with bronchogenic carcinoma. The technique has been widely accepted for clinical staging as a guide to operability and prognosis. We report on a consecutive retrospective series of 110 patients undergoing mediastinoscopy between 1982-1986 for primary mediastinal lymphadenopathy in order to assess the diagnostic value and safety of the procedure. Mediastinoscopy gave a positive histological diagnosis in 74.5% of cases with no false negative results. There were no deaths and one complication only (pneumothorax). This study shows mediastinoscopy to be a safe, accurate and cost effective procedure minimising hospital stay and allowing appropriate treatment to be immediately commenced upon diagnosis. Mediastinoscopy obviates the need for expensive computed tomography or nuclear magnetic resonance scans and we conclude that it is the investigation of choice for primary mediastinal lymphadenopathy after confirmation by plain chest radiography.

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.

Treatment of stage I lung cancer (T1N0M0, T2N0M0)

Patients with stage I lung cancer can be offered surgical treatment with an excellent prognosis for recovery and long-term cure. The recent revision of the staging definition has rearranged the prognostic categories, further improving the prognosis in Stage I disease by eliminating patients with a higher risk of recurrence. The most vexing issues remaining are the infrequency of diagnosis of lung cancer at this stage and the increasing incidence of lung cancer of all stages, even among nonsmokers. Economical screening, abolition of cigarette smoking, control of airborne environmental carcinogens, and the continued search for effective systemic treatment remain challenges for the future.

The role of surgery in N2 lung cancer

Whereas most physicians believe that long-term survival is unlikely when mediastinal lymph node metastases are present, a significant number of these patients do have resectable tumors with encouraging long-term survival results. Data are presented to support this view, and steps identified to guide the physicians in selecting the patients who can benefit from this surgical approach.

The role of mediastinal and multi-organ CT scans in staging presumable surgical candidates with non-small-cell lung cancer

In order to evaluate the role of CT scan and bone scan in staging patients with non-small-cell lung cancer presumably indicated for surgery, 70 consecutive patients who underwent thoracotomy were reviewed. Most of them received mediastinal and multi-organ (brain, liver and adrenal) CT scans and a bone scan. In the most recent 40 of the 70 patients, CT findings of the mediastinal lymph nodes were compared to the pathology following complete sampling. The overall accuracy of the mediastinal CT was 60.0 per cent (12 true positive and 12 true negative), but the negative predictable value was 12/(12 + 3) or 80.0 per cent, whereas 3 were false negatives though they showed an acceptable postoperative course. Sixteen out of 21 patients with one, or at the most, three enlarged nodes detected on CT also did well postoperatively and retrospectively, were considered not to have required mediastinoscopy. A group of patients showing no, or at the most, three enlarged mediastinal lymph nodes on CT may be considered as candidates for surgery even without mediastinoscopy. Multi-organ survey by means of CT was believed cost-ineffective and omittable. Bone scan however, retrospectively detected three true positives among 20 patients with a positive uptake, so that it cannot be omitted out of hand, though further examination of this point is required.

Role of mediastinoscopy in pretreatment staging of patients with primary lung cancer

Since the introduction of mediastinoscopy, there has been a great deal of discussion regarding indications for this technique and the significance of positive findings. We undertook this study to determine the role of clinical staging and the value of routine mediastinoscopy in the treatment selection of patients with primary lung cancer. From 1975 to 1983, 1,259 consecutive patients with proven and operable lung cancer underwent preresection mediastinoscopy. Nodes were sampled at three levels, and findings were recorded by location, invasiveness, and histology. There were no operative deaths, but 3 patients had a major complication. Mediastinoscopy was positive in 339 (27%) patients and negative in 920 (73%). In the group with positive findings, 303 patients had no operation because a curative resection was not possible (extranodal metastases, 180; location, 76; histology, 47). No patient survived 5 years, and only 4% survived 2 years. Of the 36 patients considered to have operable disease, 28 underwent resection with a projected 5-year survival of 18%. In the group with negative findings, 89% had a curative resection with a hospital mortality of 3.2% and 5-year survival of 53%. When results of mediastinoscopy were correlated with findings at thoracotomy, the sensitivity of the test was 93% on nodes in the superior mediastinum and the specificity, 100%. This study shows that mediastinoscopy is safe and is an accurate indicator of the presence or absence of tumor in superior mediastinal nodes. If positive nodes are found, a curative resection is generally not possible, thoracotomy is avoided, and the overall survival is low.

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.