70: Techniques for Staging and Restaging of Lung Cancer

Introduction

Lung cancer is the leading cause of cancer death in the United States in both men and women. In 2011, there were an estimated 221,000 new cases of lung cancer and 156,900 estimated deaths owing to the disease.¹ When indicated, surgery is the most effective curative therapy for lung cancer. For patients with limited non–small-cell lung cancer (NSCLC), lung resection remains the therapy of choice, offering the greatest potential for cure and long-term survival. Surgery also may play a limited role in small-cell lung cancer. However, of patients who present initially with lung cancer, 55% have distant metastatic disease, 30% have disease spread to regional lymph nodes, and only 15% have disease confined to the lung.² Thus, accurate staging in lung cancer is an essential component of management and prognosis.

After primary tumor diagnosis, in addition to evaluating for distant spread and assessing lung reserve and comorbidities, evaluation of the mediastinum and mediastinal lymph nodes is vital to defining tumor stage and subsequent surgical planning. Despite advances in technology, mediastinoscopy remains an important tool for the thoracic surgeon in the staging of bronchogenic carcinoma, as well as in the diagnosis of disease in the mediastinum, as described in Chapter 156.

Originally described by Carlens in 1959,³ mediastinoscopy has been the subject of a number of studies. It has been shown to be a safe procedure, with morbidity rates between 0.6% and 3.7% and mortality rates ranging from 0% to 3% in several large series.⁴ In comparison with noninvasive diagnostic procedures, such as CT scanning and MRI, studies have shown a sensitivity for cervical mediastinoscopy ranging from 0.44 to 0.92.⁵ Specificities and positive predictive values of 1.00 have been described, but this is often secondary to the study design, with reference made to findings during mediastinoscopy, rather than actual disease at various lymph node stations. Although mediastinoscopy is currently the “gold standard” for assessing lymph node status (its negative predictive value is >90%), this chapter also addresses other existing and emerging imaging modalities that can be used to augment staging accuracy. The indications and contraindications to cervical mediastinoscopy are outlined in Table 70-1.