Overview
Lung cancer refers to the uncontrolled cell growth in lung tissue. The main risk factor for lung cancer is exposure to tobacco smoke, with smoking accounting for 80-90% of lung cancer cases. Other causes of lung cancer include genetic factors, asbestos exposure and air pollution.
Primary lung cancer is a cancer that starts in the lung. The lungs are the most common site for primary cancer worldwide. Metastatic (or secondary) lung disease, on the other hand, is when cancerous cells spread to the lung from other parts of the body. The lungs are also one of the most common site for metastasis from cancers from other organs.
Symptoms
Lung cancer has a variety of symptoms, including persistent coughing, wheezing and shortness of breath (called dyspnoea), as well as coughing up blood (called haemoptysis), especially in smokers. You may also notice weight loss, fever, fatigue and deformities in the fingers and fingernails (called finger clubbing).
Compression and invasion of structures near the lung tumour can also cause other symptoms, including chest pain, hoarseness, and swelling of the face and neck (if there is a blockage preventing blood flowing back to the heart, resulting in a condition called superior vena cava obstruction).
Diagnosis
There are a number of tests which can be used to diagnose lung cancer. The first step often is made by taking a chest X-ray. CT (or CAT) scan can also be used to provide more details about the type, location and extent of the cancer.
In most cases, a specialist will also have to perform a biopsy to obtain and examine a tumour sample. This is usually done by way of a bronchoscopy, where the specialist inserts a narrow tube (scope) through your mouth or nose and windpipe, into your lungs, and then takes small tissue samples using a tiny device. It can also be done with an image-guided needle biopsy, where the specialist inserts a needle through the skin and the chest wall using CT as guidance to take a small tumour sample.
If the cancer is in the very top of a lung and the specialist suspects that it has invaded the network of nerves in your neck and chest (called the brachial plexus) or your vascular system, you may undergo an imaging technique called magnetic resonance imaging (MRI).
A further way of detecting some types of cancerous cells is an imaging technique called positron emission tomography (PET), which involves injecting a small amount of a tracer in a vein that travels through your blood, collects in organs and tissues, and allows the specialist to see the cancer more clearly.
Treatment
The treatment options available to the patient depend on the specific characteristics of the cancer, including its cell type, location, whether or not it has metastasised, and how well the patient’s heart and respiratory system are working.
Surgery is considered the main curative treatment. If surgery is not an option for a patient, and the disease is limited to the lung, an interventional radiology technique called image-guided ablation can play a major role. This procedure is performed by inserting a needle through the skin and the chest wall right into the tumour, using image guidance. The tumour is then destroyed by delivering heat (radiofrequency ablation or microwave ablation) or a gas that freezes the tissue (cryoablation).
Patients who suffer from small cell lung carcinoma or incurable cancer can improve the quality and length of their lives by undergoing chemotherapy and radiotherapy (in which high-energy X-rays are aimed at the site of the cancer).