Lung cancer, also known as lung carcinoma or bronchial carcinoma, can develop in all sections of the lungs. The majority of lung tumours develops from the cells of the membrane lining the bronchi. Often, changes to the membrane occur in an early phase of the disease and can be recognised as precursors of cancer.
More than 50 per cent of the tumours develop in the upper parts of the lobes. These are ventilated more intensively and are thus exposed more to harmful substances.
There are various types of lung carcinoma:
The so-called small-cell lung carcinoma is particularly malignant. It grows very quickly and rapidly spreads through the body.
The non-small cell lung carcinoma, including squamous-cell carcinoma, adenocarcinoma and large-cell carcinoma, grows more slowly.
Only histological examination of the cancerous tissue can reveal the exact type of tumour.
In Germany, lung cancer is one of the most common malignant diseases. In both men and women lung cancer is the third most common malignant tumour disease. Annually, approximately 34,000 men and 15,600 women develop this cancer.
While the number of new cases in men has been declining slowly since the end of the 1980s, it has been rising steadily in women. Lung cancer mostly occurs in patients older than 40. Most patients are 69 years old.
90 per cent of cases can be traced back to smoking.
Different criteria are significant in terms of risk:
- the number of cigarettes smoked
- how long patients have been smoking for
- the concentration of harmful substances in the cigarette
- the point when patients first started smoking
Giving up smoking reduces the risk of lung cancer. After 10 years, former smokers have approximately the same risk of developing lung cancer as non-smokers.
The risk of developing lung cancer is also increased by passive smoking.
In addition, there are a number of substances that are inhaled in the workplace or because of a high rate of pollution in the air. Diet, infections and possibly genetic factors also play a role in the occurrence of lung cancer.
90 per cent of all lung cancer cases can be traced back to smoking. Cigarette smoke contains a number of substances that can cause cancer (carcinogenic). The more cigarettes are smoked a day and the longer people smoke the higher their risk of developing lung cancer. Consequently, 25 cigarettes a day mean that the chance of developing lung cancer is 25 times that of a non-smoker.
The earlier lung cancer is detected the better the prognosis. In the early stages, lung cancer rarely causes symptoms. Therefore, very small lung carcinoma are almost always only detected by chance, for example during x-rays.
The following symptoms may occur and should be assessed by a doctor:
- A cough lasting for several weeks that does not go away but gets worse or changes suddenly
- Bronchitis, or a “cold” that does not improve with antibiotics
- Shortness of breath
- Constant chest pain
- Sputum with or without blood
- Swelling in the neck and face
- Loss of appetite and extreme weight loss, general loss of energy
- Paralysis or severe pain, bouts of fever
If lung cancer is suspected, physicians will initiate the appropriate examinations. They are used to determine whether a tumour is present. If this is the case, the tumour type and stage of the disease is determined.
The basic examinations for suspected lung cancer include:
- Laboratory testing of blood and bronchial mucus
If lung cancer is suspected a bronchoscopy is one of the standard examinations. Abnormal cells in the lungs can be detected with an optical device called bronchoscope.
If lung cancer is confirmed further examinations will follow. These will show how far the tumour has spread, whether lymph nodes are affected and whether metastases have grown in other regions of the body.
These examinations include:
- Computer tomography (CT)
- Magnetic resonance imaging (MRI)
- Ultrasound (sonography)
- Bone scan (sceletal scintigraphy)
- Positron emission tomography (PET)
- Endobronchial ultrasound (EBUS)
- Lung function test
- Bone scan (sceletal scintigraphy)
A bone scan will reveal whether the tumour has spread to the bones. For this, small amounts of a radioactive substance which accumulates in particular in diseased bone are injected into the blood. A camera makes the radiation visible.
Positron emission tomography (PET)
During a PET scan, radioactively marked glucose is injected into the blood and its metabolism is visualised. Compared to healthy tissue, tumours and metastases exhibit increased metabolism in most cases and can thus be differentiated from healthy tissue in the image.
Bronchial carcinoma often spread through the lymphatic vessels. The lymph nodes in the space between the two lobes of the lung (mediastinum) are affected particularly commonly. A mediastinoscopy can be useful if the choice of treatment depends on the best possible assessment of the state of those lymph nodes.
Endobronchial ultrasound (EBUS)
In this examination, a bronchoscopy is combined with an ultrasound. An ultrasound head is located at the tip of the bronchoscope to visualise and puncture the lymph nodes in the mediastinum.
Lung function test
A lung function test is used to determine the functional state of the lungs.
The choice of therapy depends significantly on the type of lung cancer (non-small cell or small cell) and on how far the disease has advanced when diagnosed.
The following therapy options are available:
- Radiation therapy
The choice of therapy depends on the type of tumour and the stage of the disease. If considered useful, the different therapies can be combined.
During chemotherapy, so-called cytostatics (cell-destroying medicinal products) are used to inhibit cell growth. As cancer cells grow particularly rapidly they are more sensitive to cytostatics than healthy cells.
If the tumour has not exceeded a certain size and no distant metastasis is present, surgery is always the first choice. Surgery aims to completely remove the tumour tissue and the surrounding lymph nodes if the cancer has spread there. This type of surgery is particularly important in the treatment of non-small cell lung cancer. In some cases it may also be indicated in small-cell lung cancer if the tumour is still small in size and only the surrounding lymph nodes have been affected.
The tumour region is targeted with external radiation. Radiation therapy causes the destruction of cancer cells.
In non-small cell lung tumours radiation may be used if the tumour is so large already that surgery alone will not be enough to remove it entirely.
Generally, radiation therapy is used in combination with chemotherapy.
In chemotherapy, so-called cytostatics - medicinal products that inhibit cell growth - are used. They mainly counteract fast-growing cells and therefore cancer cells. For the treatment of lung cancer several chemotherapeutic medicinal products are available and selected depending on the individual circumstances.
Depending on the spread of the tumour, lung cancer is divided into different stages. An exact classification is necessary for choosing the right treatment. For classification, certain standards are used, with the main three aspects being:
size and spread of the tumour (T)
involvement of lymph nodes (N)
presence of metastasis (M)
Thus the term TNM classification is used, which is an internationally recognised system. The numbers after the letters allow for a further specification of the tumour size (T1-4), the number and location of the affected lymph nodes (N0-3) and the presence or absence of distant metastasis (M0 and M1). If stage “T1 N0 M0” has been noted in the patient file by the physician this means that the tumour is small in size and has not spread to the main bronchus, no lymph nodes are affected and there is no metastasis.
T1 = The primary tumour is no more than 2 cm (T1) or between 2 and 3 cm (T1b) in size without involvement of the main bronchus.
T2 = The primary tumour is larger than 3 cm and smaller than 5 cm (T2a) or between 5 and 7 cm (T2b) in size or growing into the main bronchus of the same side.
T3 = The primary tumour is larger than 7 cm or has invaded into the chest wall, diaphragm, lining of the lungs or the pleura, or a main bronchus. Separate tumour nodules in the same lobe.
T4 = The tumour has invaded surrounding structures such as the space between the two lungs (mediastinum), heart, blood vessels, trachea, or vertebral body. Separate tumor nodule in a different lobe of the same lung.
N0 = The lymph nodes are not affected
N1 = The tumour has invaded surrounding lymph nodes on the same side
N2 = The tumour has invaded more distant lymph nodes on the same side
N3 = The tumour has invaded lymph nodes of the other lung lobe
M0 = No clinical evidence of distant metastasis
M1 = Evidence of distant metastasis (M1b, e.g. in the liver, brain, adrenal glands or bones) or malignant infiltration of the pleura or the pericardium (M1a)