The lungs are the part of the body that we use to breathe. The primary function of the respiratory system is to load blood with oxygen in order for the blood to deliver that oxygen to the body.
The lungs form part of the respiratory system which is made up of several parts:
- Mouth and nose.
- Windpipe (trachea).
- The right main bronchus and the left main bronchus (airways to each lung).
- The lungs.
Facts and figures of lung cancer
Lung cancer is the 2nd most common cancer in the UK, with over 40,000 new cases diagnosed every year in the UK. Age-related, being rare in those under 40 years of age and most commonly diagnosed in those 70+ years.
Higher incidence in men, the male to female ratio being 12:10. The main risk factor is tobacco smoking which accounts for approximately 86% of cases, further 3% attributed to passive smoking.
Other causes include exposure to certain substances such as asbestos, silica, arsenic and coal. Air pollution and family history of lung cancer are also risk factors.
There are two main types of lung cancer, the most common type are non-small cell carcinomas which account for approximately 87% of cases and these can be divided into 3 groups, the most common being squamous cell carcinomas than adenocarcinomas, the incidence of which is increasing and also undifferentiated large cell; there are a few cases where the tumours are mixed. The other type is small cell carcinomas which account for approximately 12% of cases.
Symptoms and signs of lung cancer
Lung cancer develops in the cells of the lung and stops those cells from taking on oxygen and carrying it around the body. This can make breathing very painful and leave you feeling extremely fatigued.
The main symptoms of lung cancer are:
- A persistent cough.
- Shortness of breath.
- Chest pain/ aches and pains when breathing or coughing.
- Blood in sputum (haemoptysis).
- Recurring chest infections (not responding to antibiotics).
There are four main types of lung cancer that split into small cell (named after their appearance under the microscope) and non-small cell variations. These are treated differently. However, 80% of cases are non-small cell lung cancer.
Lung cancer diagnosis
If the symptoms are suspicious, the GP will refer a patient to a consultant who will carry out a careful examination to determine the type, size, location and the character of the tumour along with together with any potential evidence of spread (metastasis).
Investigations that may be used to fully assess lung cancer may include:
- Physical examination.
- Blood tests.
- Chest x-ray.
- Liver function tests.
- Bronchoscopy- tissue samples may be taken for biopsy.
- Endobronchial ultrasound -tissue samples may be taken for biopsy.
- CT scan.
- PET-CT scan.
- Percutaneous lung biopsy-– local anaesthetic is used, a tissue sample is acquired by putting a needle through the skin into the lung using CT scan or ultrasound to guide the needle.
- MRI scan (not often used to diagnose primary tumour but brain MRI or CT scan may be performed to ascertain if there is any spread of disease to the brain).
- Bone scan (used for staging, investigating if the disease has spread to the bones).
- Neck node biopsy- if CT scan indicates changes in neck lymph nodes, these may be biopsied to investigate if there are any cancer cells in the lymph nodes).
Metastases occur when cancer cells break off and spread through the lymphatic channels or blood vessels to settle in other parts of the body. With lung cancer secondary tumours in the bone, liver and brain are the most common.
Treatment for lung cancer
Depends on several factors:
- The type of lung cancer:
- The position of the tumour in the lung.
- The stage of cancer.
- General health.
Treatment for small cell lung cancer
Surgery is not often recommended for small cell tumours unless diagnosed at a very early stage. It is only suitable if there is no sign that cancer has spread to the lymph nodes in the centre of the chest. Unfortunately, the disease has usually spread beyond the lung at diagnosis.
Chemotherapy is the main treatment for small cell lung cancer, sometimes in combination with radiotherapy. Small cell tumours tend to respond well to chemotherapy and it will treat any disease which may have spread outside of the lungs.
Radiotherapy may be given after chemotherapy or at the same time (concomitant chemoradiation). Also, if the chemotherapy is effective and shrinks the tumour, radiotherapy to the brain may be recommended (prophylactive radiotherapy) to kill any cells that may have already spread but are too small to detect and are not causing any symptoms. This has been found to reduce the risk of brain secondaries from 54% to 30% at 2 years after diagnosis.
Treatment for non-small cell carcinoma
In the early stages, surgery will normally be used to remove part of the affected lung (lobectomy) or the entire lung (pneumonectomy).
Chemotherapy may be recommended after surgery to reduce the risk of recurrence, particularly if cancer cells are found in the lymph nodes at surgery, it may be advised in combination with radiotherapy.
Radiotherapy is likely to be recommended if removal of the whole tumour was not possible at surgery. It may also be recommended if the position of the tumour and cancer cells or the general health of the patient excludes surgery. Radiotherapy may be given in combination with chemotherapy and if patients are fit enough and have small tumours they may be given at the same time (concomitant radiotherapy), giving these treatments together does increase the side effects.
Radiofrequency ablation (RFA)
If surgery is not an option, then RFA may be considered .It is given under local anaesthetic or general anaesthetic. A small probe goes through the skin and directly into the tumour. The treatment is usually done under CT scan guidance. An electrode in the probe then creates radiofrequency energy to produce heat and destroy the tumour cells.