Auxiliary examination for lung cancer

Auxiliary examinations for lung cancer include:

(I) Bronchoscopy

An important auxiliary examination in the diagnosis of lung cancer is fiberoptic bronchoscopy. Bronchial biopsy, brushing, lavage, and transbronchial needle biopsy are commonly used to diagnose most bronchopulmonary malignancies. Bronchial biopsy is more sensitive than bronchial lavage and brushing for diagnosing lung cancer. Since small cell lung cancer lesions can be located under the bronchial mucosa, biopsy is particularly sensitive. If the tumor can be seen under the microscope, the positive rate of bronchial lavage and brushing is about 75%, biopsy is about 85%, and the combined positive rate of biopsy, brushing, and bronchial lavage is 94%. On the contrary, if the tumor cannot be seen under the microscope, the positive rate of brushing and bronchial lavage is 50%, and the positive rate of biopsy is 60%.

(ii) Transthoracic needle biopsy

Transthoracic needle aspiration biopsy is helpful for the diagnosis of lung diseases that cannot be found by bronchoscopy. It can be performed under the guidance of a fluorescent screen, a sonogram, and chest CT. Since transthoracic needle aspiration biopsy has a certain false negative rate, and the possibility of malignant lesions cannot be ruled out if the biopsy is benign or the diagnosis is uncertain, no matter what the transthoracic needle aspiration biopsy result is, as long as the patient is suitable for thoracotomy, surgery should be performed to clarify the diagnosis and treatment. The indications for transthoracic needle aspiration biopsy are: patients with lung masses who are not suitable for thoracotomy but need to be diagnosed; patients with a history of malignant tumors and new lesions in the lungs.

3. Mediastinoscopy

There are differences in the role of mediastinoscopy in the diagnosis and staging of lung cancer. When non-invasive staging tests indicate the presence of mediastinal lymph node metastasis, mediastinoscopy can determine the presence of mediastinal lymph node involvement in about 70%. When CT proves that the diameter of the mediastinal lymph nodes is >10mm and it is necessary to determine that the lung cancer is inoperable, mediastinoscopy and biopsy are often recommended. However, it should be noted that many groups of lymph nodes (such as paraesophageal and para-aortic groups) cannot be examined during mediastinoscopy. In this case, mediastinoscopy can be performed using the left parasternal approach. For some patients with lung cancer, mediastinoscopy can be used to biopsy enlarged lymph nodes in these areas.

4. Thoracoscopic examination

It has been proven that thoracoscopy is most commonly used for the diagnosis of masses of unknown nature. In addition, thoracoscopy is also commonly used to determine para-aortic, subaortic arch, tracheobronchial, subcarinal, paraesophageal or hilar lymph node metastasis, and it also helps to confirm pleural invasion or dissemination. With the continuous improvement of the localization and qualitative technology of lung masses (such as chest ultrasound and preoperative acupuncture localization), the indications of thoracoscopy for lung cancer staging will expand.