Lung cancer – How is it diagnosed?

Lung cancer is the leading cause of cancer-related deaths worldwide, with smoking being the leading cause in about 85% of the cases.

The most common symptoms that may lead to diagnostic investigations are:

• Cough that doesn’t go away 
• Coughing up blood 
• Chest pain when breathing and coughing 
• Shortness of breath
• Repeated chest infections 
• Loss of appetite
• Unintentional weight loss

Other patients present without any symptoms with a tumour in the lung picked up on chest X-ray or CT scan.

Sputum cytology

If you are coughing up mucous, it can be looked under a microscope if there are any cancer cells. 

Chest X-ray

This is normally the first investigation to be done, where it will show suspicion of a lung lesion. In most cases, we are unable to differentiate the cause of the lesion from cancer, infection, or inflammation. The next investigation will be a chest CT scan. 

Chest CT scan

The chest CT scan will define the lesion in terms of size, consistency, shape, and position. The lymph nodes in the chest will be looked at to see if they are enlarged which may mean they might contain cancer cells that have spread. 

Biopsy

To get definitive diagnosis of lung cancer, you need a tissue biopsy to send to the lab for testing.

CT-guided lung biopsy

This procedure is done by a radiologist. A needle is guided from the skin to the lung lesion in the chest with a CT scan to acquire the lung lesion tissue and it’s sent to the pathologist for testing. You may be given anaesthesia or sedating medicines.

Bronchoscopy

If there is suspicion of the mass in the airways, a bronchoscopy will be done by a pulmonologist or thoracic surgeon to get a biopsy. It entails a thin tube with a camera that goes into the airways. You will be given a sedative to help you relax and a liquid medicine to numb your nose and throat or it can be done under general anaesthesia.

Thoracoscopy

The thoracoscopic procedure is done by a thoracic surgeon were two or three small cuts will be made on the chest and a camera is inserted to view the whole lung, lining of the lung, and chest wall. A biopsy is then taken of the lung lesion. 

This procedure is commonly done when the CT-guided lung biopsy can’t be done due to position of the lung tumour with the surrounding structures or failed CT-guided biopsy. This is done under general anaesthesia.

Staging 

Once the lung cancer is confirmed on lung tissue, it will be staged. We need to determine the spread of the lung cancer which then determines the treatment that is needed. This stage of the disease can be handled by a pulmonologist, thoracic surgeon, or oncologist. 

Further investigations

With further investigations being whole body PET-CT scan and MRI brain. 

Large lymph nodes in the chest can be sampled to test for cancer spread via:

Endobronchial ultrasound-guided transbronchial needle aspiration (EBUS)

A scope camera is inserted in the airway and under ultrasound vision, a needle is guided through the airways to the enlarged lymph nodes. No incision is necessary. This is done under general anaesthesia.

Mediastinoscopy

Incision in the neck, then a scope is inserted behind the breastbone to sample the enlarged lymph nodes. This is done under general anaesthesia. 

MDT to plan treatment

After staging the lung cancer, there is usually a multi-disciplinary meeting between oncologist, pulmonologist, and thoracic surgeon in terms of the appropriate treatment required for the patient.

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