I. Sputum exfoliative cell examination
If sputum specimens are collected properly, a series of 3 or more sputum specimens can increase the diagnostic rate to 80% for central lung cancer and 50% for peripheral lung cancer. Other factors affecting the accuracy are: the presence of purulent secretions in the sputum can cause liquefaction of malignant cells; and the ability of cytopathologists to identify malignant cells.
Fiberoptic bronchoscopy and electronic bronchoscopy
Useful for diagnosis, determining the extent of lesions, and clarifying the indications and modalities of surgery. The diagnostic rate of endobronchial lesions visible by fiberoptic bronchoscopy can reach 92% by brush examination and 93% by biopsy. Transbronchial lung biopsy (TBLB) can improve the diagnosis of peripheral lung cancer. For lesions larger than 100px in diameter, the diagnostic rate can reach 50%-80%. However, for lesions less than 50px in diameter, the diagnosis rate is only about 20%. Cytological examination of lavage and brushings during fibrinoscopy can also provide important diagnostic assistance.
Comorbidities of fibrinoscopy are rare, but laryngospasm, pneumothorax, hypoxemia and hemorrhage can occur during the examination. Pulmonary hypertension, hypoxemia with carbon dioxide retention and hemorrhage should be listed as contraindications to lung biopsy.
Needle aspiration cytology
Needle aspiration cytology can be performed percutaneously or via fibrinoscopy. It can also be performed under ultrasound, X-ray or CT guidance, and is currently commonly used mainly for superficial lymph node and ultrasound-guided needle aspiration cytology.
Needle aspiration cytology of superficial lymph nodes: Needle aspiration cytology can be performed on enlarged superficial lymph nodes in the supraclavicular or axillary area under local anesthesia or even without anesthesia. A high diagnostic yield can be obtained for lymph nodes with a stiff texture and poor mobility.
Transluminal needle aspiration cytology: For peripheral lesions and enlarged lymph nodes or masses adjacent to the trachea or bronchi, transluminal needle aspiration cytology can be performed. When combined with TBLB, it can increase the diagnosis of central lung cancer to 95%, compensating for missed diagnoses when submucosal lesions are not caught by biopsy forceps.
Percutaneous needle aspiration cytology: Needle aspiration biopsy can be performed under ultrasound guidance if the lesion is close to the chest wall, and puncture needle aspiration or biopsy can be performed under fluoroscopic or CT guidance if the lesion is not close to the chest wall. False-negative results may occur due to the limited number of cells aspirated by needle aspiration. Repeat examinations may be performed to improve the diagnostic yield. Approximately 29% of lesions initially negative on cytology are found to be malignant after several repeat examinations. A common complication of percutaneous needle aspiration cytology is pneumothorax, with an incidence of about 25-30%.
Mediastinoscopy
Mediastinoscopy is an invasive test for evaluation and biopsy of mediastinal metastatic lymph nodes. It is beneficial to the diagnosis of tumor and TNM staging.
V. Thoracoscopy
It is mainly used to determine the nature of pleural effusion or pleural mass.
Other cytological or pathological examinations
Such as cytological examination of pleural effusion, pleural, lymph node, liver or bone marrow biopsy.
VII. Open-chest lung biopsy
If the cytological diagnosis cannot be established by sputum cytology, bronchoscopy and needle biopsy, open chest lung biopsy will be considered, but the decision must be made after carefully weighing the pros and cons according to the patient’s age and lung function.
VIII. Tumor marker examination
There are many markers for lung cancer, including proteins, endocrine substances, peptides and various antigenic substances such as carcinoembryonic antigen (CEA) and soluble membrane antigens such as CA-50, CA-125, CA-199, and certain enzymes such as neurospecific enolase (NSE), cyfra21-1, etc. Although they are helpful for the diagnosis of lung cancer, they lack specificity. It has some reference value for disease monitoring of certain lung cancers.
Treatment options are mainly determined by the histology of the tumor. Usually, SCLC is metastatic at the time of detection and is difficult to be eradicated by surgery, relying mainly on a combination of chemotherapy or radiotherapy. In contrast, NSCLC can be limited and can be cured by surgery or radiotherapy, but has a poorer response to chemotherapy than SCLC.
IX. Non-small cell lung cancer (NSCLC)
Surgery: Surgery is preferred for stage la, lb, IIa and IIb NSCLC that can tolerate surgery. Surgery may also be considered for stage IIIa lesions if the patient’s age, cardiopulmonary function, and anatomic location are appropriate. Preoperative chemotherapy (neoadjuvant chemotherapy) may allow many previously inoperable patients to be downgraded to surgery, and thoracoscopic television-assisted thoracic surgery (VATS) may be used in patients with peripheral type lesions with poor lung function.