Invasive staging of non-small cell lung cancer--a prospective study

Clinical prognosis and treatment schedules of non-small cell lung cancer (NSCLC) are dependent on tumor stage. This explains the importance of an exact pretreatment staging of the primary tumor and lymph nodes especially in locally advanced NSCLC, to differentiate between resectable and non-resectable disease. To assess the lymph node status of the upper mediastinum, the diagnostic value of mediastinoscopy is accepted to be superior to radiological methods. In contrast, thoracoscopy is not yet established as a standard staging tool.

Seventy-three consecutive patients with CT-based suspicion of advanced NSCLC have been investigated as part of a phase II study on neoadjuvant treatment of NSCLC. All patients underwent mediastinoscopy and mediastinal lymph node sampling. In the case of a negative result we performed additional thoracoscopy.

In 52.1% (n = 38) of the patients the invasive diagnostic methods led to results that were effectively different from those of the radiological findings. In 11 patients (15.1%) CT-assessed lymph node metastases could invasively not be confirmed, whereas nine patients (12.3%) had positive mediastinal lymph nodes but no corresponding CT signs (diameter <1 cm). The results were achieved by mediastinoscopy in 15 (20.5%) and by thoracoscopy in five (6.8.%) patients. A radiologically unexpected T4 stage has been found in four (5.5%) and a M1 stage in four (5.5%) patients by thoracoscopy. On the contrary, in seven patients a suspected infiltration of mediastinum or parietal pleura could be thoracoscopically excluded. Four patients have been in an unexpected high stage of tumor progression at the moment of diagnostic procedures and therefore have been included in palliative therapy schedules. Ten patients have been 'overstaged' by radiological methods and benefited from a primarily curative resection after invasive staging.

Of the 73 prospectively studied patients with locally advanced NSCLC, 12 (16.4%) have been staged too low and 13 (17.8%) too high. If exclusively staged by radiological methods, about 34% of lung cancers have been classified incorrectly. Therefore, these tools are not a sufficient basis for diagnosis of stage III NSCLC disease. Mediastinoscopy with consecutive thoracoscopy is an essential part of the therapeutic planning in locally advanced NSCLC, and results are significantly superior to clinical staging.