Small cell lung cancer: Description
Small cell bronchial carcinoma is the second most common form of lung cancer (after non-small cell bronchial carcinoma) with a share of about 12 to 15 percent – the disease often occurs between the ages of 60 and 80.
The starting point for small cell lung cancer is formed by so-called APUD cells in the bronchial mucosa. These are cells that contain various small protein pieces (peptides) and their precursors (APUD = Amine Precursor Uptake and Decarboxylation).
If you look at a small cell bronchial carcinoma under the microscope, the cancer cells appear small, flat and close together. Because the cells also visually resemble oatmeal, this form of cancer is also called “oat cell carcinoma.” In clinical settings, doctors often refer to small cell lung cancer simply as “small cell.”
How does small cell lung carcinoma grow?
In addition, small cell lung cancer spreads early through the blood and lymph channels to other parts of the body, where daughter tumors (metastases) then form.
The rapid growth and early metastasis make small cell lung cancer aggressive and difficult to treat – by the time it is diagnosed, it is usually already in an advanced stage.
Small cell lung cancer: symptoms
Lung cancer (such as small cell bronchial carcinoma) usually presents with only nonspecific symptoms at first. These include, for example, a persistent cough, chest pain and fatigue. Many patients do not take these symptoms seriously. Smokers, for example, simply attribute such complaints to smoking. Others suspect a persistent cold or bronchitis.
Because small cell bronchial carcinoma spreads quickly, other symptoms are soon added. These can include shortness of breath, bloody sputum, fever, rapid weight loss and night sweats.
Read more about the general symptoms of lung cancer and the specific symptoms of small cell lung cancer in the text Lung cancer: symptoms.
Small cell lung cancer: Causes and risk factors
The main risk factor for small cell lung cancer (and lung cancer in general) is smoking. Especially people who started smoking early in life and/or smoke heavily easily develop a malignant tumor of the lung. But not only active smoking, but also passive smoking increases the risk of lung cancer.
In addition, there are other risk factors for lung cancer. These include, for example, contact with asbestos and high levels of pollutants in the air.
You can read more about the possible triggers of bronchial carcinoma under Lung cancer: causes and risk factors.
Small cell bronchial carcinoma: examinations and diagnosis
This is followed by a physical examination and various instrumental examinations. The doctor will take an X-ray of the chest (chest X-ray). Pathological changes can often already be detected on this. A computer tomography (CT) provides detailed images. Further examinations can confirm the suspicion of lung cancer and help to determine the spread of the tumor.
You can read more about the various examinations and tests for bronchial carcinoma under Lung cancer: examinations and diagnosis.
Small cell lung cancer: treatment
Generally, the main treatment approaches available for small cell bronchial carcinoma (and other forms of lung cancer) are as follows:
- surgical removal of the tumor
- radiation therapy of the tumor (radiotherapy=
- chemotherapy with drugs that inhibit cell division
The individual therapy methods can be combined in different ways, whereby the lung cancer stage and the general condition of the patient are the most important factors. In this way, each patient receives an individually suitable therapy.
Treatment in very early stages (very limited disease)
In rare cases, small cell lung cancer is still in a very early stage at the time of diagnosis: the tumor is confined to a small area in the lung and has not yet metastasized to distant sites. Doctors refer to this as “very limited disease”.
In this very early stage of the disease, small cell lung cancer is still operable and thus, in principle, curable. However, to be on the safe side, patients also receive chemotherapy. This can either take place before the operation (neoadjuvant chemotherapy) in order to reduce the size of the tumor for the operation. Or chemotherapy is given after surgery to eliminate any remaining cancer cells (adjuvant chemotherapy).
If cancer cells can already be detected in lymph nodes, patients usually also receive radiation therapy. In any case, cranial irradiation is performed as a precautionary measure, because small cell lung cancer often forms metastases in the brain.
Treatment in the middle stage (limited disease)
Surgery is usually no longer possible at this stage. Instead, patients are usually treated with a combination of chemotherapy and radiotherapy (radiochemotherapy). As a precaution, the skull is always irradiated as well.
Treatment in advanced stages (extensive disease)
In most patients, the lung tumor has already reached the “extensive disease” stage at the time of diagnosis. This means that the tumor has already metastasized to other parts of the body. A cure is then usually no longer possible. Patients receive what is known as palliative therapy, which aims to alleviate symptoms and prolong the patient’s survival time as far as possible.
For this purpose, patients receive chemotherapy – i.e. drugs that block the rapid growth of cancer cells (cytostatics). This can usually temporarily push the tumor back.
In addition, the skull is irradiated: this is intended to prevent brain metastases or to combat existing metastases. In certain cases, the primary tumor in the lung is also irradiated.
New therapeutic approach
Since 2019, there is also another therapeutic option for advanced-stage small cell lung cancer – the combination of standard chemotherapy with immunotherapy:
In addition to cytostatics, patients also receive the immunotherapeutic drug atezolizumab. This is a so-called immune checkpoint inhibitor: it blocks the protein PD-L1 produced by the cancer cells. This prevents the immune system from acting against the cancer.
By blocking PD-L1, atezolizumab can therefore reverse the suppression of the immune defense – the body’s defense system is able to attack the tumor more effectively. However, treatment with immune checkpoint inhibitors does not work for all patients.
Atezolizumab can also be used to treat advanced-stage non-small cell lung cancer – the most common form of lung cancer.
Small cell lung cancer: prognosis
In the rarer cases where small cell lung cancer is detected at an early stage, there is still a chance of cure if treated immediately and correctly.
Read more about prognosis and chances of cure for bronchial carcinoma in the text Lung cancer: life expectancy.
