The detection of most lung cancers relies on imaging, but the sensitivity and specificity of imaging tests are not satisfactory for confirming the diagnosis. Currently, pathological examination remains the gold standard for lung cancer diagnosis.
Ultrasound/fiberoptic bronchoscopy, percutaneous lung puncture, mediastinoscopy, and surgical resection are among the important ways to obtain tissue samples during pathologic examination. With so many diagnostic techniques available, why do we still emphasize the importance of “open-chest exploration” to confirm lung cancer diagnosis?
The limitations of each of these “sampling” techniques
Bronchoscopy
- Bronchoscopic sampling can be used for pathologic confirmation when the tumor is near the center or clearly invades the bronchus. In patients who are unable to obtain a primary focus, but have mediastinal lymph node enlargement, ultrasound bronchoscopy can help us to clarify the pathology and genotyping.
- For peripheral nodules that are not close to the center, or that do not invade the bronchi, ultrasound bronchoscopy, or magnetic navigation bronchoscopy is often required to have access to tissue samples, but it is expensive.
Percutaneous pulmonary puncture
- It is the most common diagnostic technique used in medical oncology. It allows more tissue to be extracted and causes less trauma and discomfort than bronchoscopy. However, percutaneous pulmonary puncture is similarly unable to retrieve tissue specimens for tumors that are richly vascularized, or where the tumor itself is near vital organs or large blood vessels, or where the tumor is located in the middle band of the lung.
Mediastinoscopy
- One of the major advantages of mediastinoscopy over electronic bronchoscopy is that more tissue can be retrieved. Also through parasternal mediastinoscopy, samples of the main pulmonary window and lymph nodes adjacent to the ascending aorta can be obtained.
- However, it can’t do anything for the paraesophageal lymph nodes, which can only be sampled by ultrasound endoscopic aspiration biopsy. In addition, mediastinoscopy is much more difficult if you have a combination of superior vena cava syndrome, previous mediastinal radiation therapy, or a median sternotomy.
These conditions require open-chest exploration
Chest exploration may be needed to clarify the diagnosis if you have either of the following two conditions:
- Early to mid-stage operable, the examination reveals intrapulmonary nodules/occupations. Open-chest exploration allows the pathological tissue to be retrieved for a clear diagnosis on the one hand, and direct complete removal of the tumor on the other, killing two birds with one stone.
- Sublobar resection can be considered in cases where there is a high suspicion of isolated metastases (no more than 5 metastatic lesions in a single organ) or metastases on preoperative imaging. On the one hand, it can reduce tumor load, clarify pathology and genotyping, and also guide subsequent treatment decisions.
Co-authors: Dr. Zhang Chao, Guangdong Provincial People’s Hospital, Guangdong Lung Cancer Institute