For introduction, epidemiology, and types, see the corresponding pathology 1 topic.
Lung cancer can produce many different signs and symptoms. They may be due to the intrathoracic effects, distant metastases, or paraneoplastic syndromes. Central carcinomas, like SCC and SCLC, tend to produce symptoms more often.
The most common symptom is cough, which is present in 50 – 75% of lung cancer cases at presentation. The second most common symptom is dyspnoea.
Other possible clinical features include:
- Chest pain
- Weight loss
- Stridor (due to tracheal obstruction)
- Dysphagia (due to oesophageal obstruction)
- Bone pain (due to metastases)
- Cushing syndrome (due to paraneoplastic syndrome)
- Neurological symptoms (due to metastases)
- SIADH (due to paraneoplastic syndrome)
- Superior vena cava syndrome
- Horner syndrome
- Clubbing of the fingers (due to paraneoplastic syndrome)
Diagnosis and evaluation
The initial investigation is usually chest x-ray, which may show a solitary nodule. In this case, the patient proceeds to a contrast chest CT.
For a definite diagnosis, histopathology is required. Ideally, a large enough biopsy should be taken to allow for immunohistochemical and genetic analysis, as this has implications for treatment and prognosis. There exist multiple modalities for obtaining biopsy, including endobronchial ultrasound-guided biopsy, transthoracic needle biopsy, transoesophageal endoscopic ultrasound, mediastinoscopy, etc.
When the diagnosis is made, several staging and preoperative investigations should be performed:
- Evaluation of performance status (ECOG)
- CT chest, abdomen, pelvis
- Brain MRI
- Pulmonary function test
- Abdominal ultrasound
The treatment for NSCLC and SCLC is different.
For NSCLC, tumours up to and including stage IIIb are potentially curable:
- Stage I – II – surgery alone
- Stage IIIa – surgery alone
- Stage IIIb – radiochemotherapy
- Stage IIIc – IV – palliative, any combination of chemo, radio, immunotherapy
For incurable NSCLC, the genetic and immunohistochemical analysis becomes important. We have specific therapy for PD-L1, KRAS, EGFR, ALK, and ROS mutations.
For SCLC, the so-called “limited disease” (cancer has not spread beyond the hemithorax, corresponds to stages I – IIIb) is curable. SCLC has a very high turnover and is therefore sensitive to radio and chemotherapy. “Extensive disease” refers to cancer which has spread beyond one hemithorax and is deemed incurable.
Prophylactic cranial irradiation is used for SCLC, as it improves survival by killing brain metastases which are often already present but not visible on scans.
Surgery is the main treatment of NSCLC stages I – IIIa. It is not used for SCLC.
Surgical options include wedge resection, segmentectomy, lobectomy, and pneumonectomy. The less invasive options are preferred if they allow for margin negative (R0) resection. Lobectomy is usually preferred over wedge resection or segmentectomy, as the risk for R1 resection is smaller, but these may be chosen if the patient is deemed to have insufficient pulmonary function to tolerate a lobectomy.
Surgery is preferably performed with video-assisted thoracoscopy (VATS) rather than open surgery.
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