NSCLC: Description
Physicians know several types of lung cancer (mediz. bronchial carcinoma). First, they distinguish two major groups: Non-small cell bronchial carcinoma (NSCLC) and small cell bronchial carcinoma (SCLC). In small cell lung cancer, many small, densely packed cells are found under the microscope. In contrast, the cells in NSCLC are larger.
Small cell and non-small cell lung cancer differ in their progression and treatment. Most patients with lung cancer have a non-small cell tumor. It can be further subdivided.
What are the different types of NSCLC?
Non-small cell lung cancer can arise from different cell types. Accordingly, the following subtypes are distinguished:
- Adenocarcinomas
- squamous cell carcinomas
- large cell carcinomas
- other non-small cell bronchial carcinomas
Adenocarcinomas and squamous cell carcinomas are the most common forms of NSCLC and of lung cancer in general. Large cell carcinomas are less common. This is even more true for other small cell bronchial carcinomas – these include variants that are very rare.
How do the different types of NSCLC develop?
Squamous cell carcinomas usually consist of solid clusters of degenerated cells that do not form mucus. They usually grow centrally in the lung, preferentially at the branching of smaller airways (bronchi). Squamous cell carcinoma of the lung usually develops as a result of chronic mucosal irritation, such as tobacco smoke.
Physicians usually speak of a large cell carcinoma when they cannot identify a non-small cell bronchial carcinoma under the microscope as either an adenocarcinoma or a squamous cell carcinoma. Thus, it is a diagnosis of exclusion. As the name suggests, the cells of this variant of cancer are strikingly large.
Special case of Pancoast tumor
A special case of NSCLC is Pancoast tumor, named after its discoverer. This fast-growing bronchial carcinoma arises at the top of the lung. It can spread very quickly to surrounding structures such as ribs, soft tissues of the neck, or the nerve plexus of an arm. Pancoast tumors are adenocarcinomas in most cases.
NSCLC: Causes and risk factors
The most important trigger for non-small cell lung cancer (and other forms of lung cancer) is smoking: The longer someone has smoked and the more cigarettes a day, the higher his or her risk for a malignant tumor in the lungs.
Other factors that promote the development of a malignant lung tumor include air pollutants, asbestos and arsenic.
To read more about how lung cancer develops and important risk factors, see Lung cancer: causes and risk factors.
NSCLC: Symptoms
Lung cancer (such as non-small cell lung cancer) usually causes few symptoms in early stages. Most patients report only nonspecific symptoms such as fatigue, cough, and chest pain. However, the further the tumor spreads, the more and more severe the symptoms become. These may include bloody sputum, shortness of breath and low-grade fever.
If a non-small cell lung cancer has metastasized to other parts of the body, the patient may experience additional symptoms. For example, brain metastases can cause headaches, impaired vision and balance, confusion and/or paralysis.
Read more about the general symptoms of lung cancer and the specific symptoms of Pancoast tumor in the text Lung cancer: symptoms.
NSCLC: examinations and diagnosis
First, the doctor will ask the patient about the exact symptoms and possible pre-existing or concomitant diseases. He will also ask whether the patient smokes or comes into contact with hazardous substances such as asbestos at work.
This is followed by a careful physical examination and various instrumental examinations. These include, for example, an X-ray examination of the chest (chest X-ray). In addition, the doctor will take a tissue sample from suspicious areas in the lungs and have it analyzed in the laboratory.
You can read more about necessary examinations for all types of lung cancer under Lung cancer: examinations and diagnosis.
NSCLC: Treatment
The different types of NSCLC are treated similarly at each tumor stage. It is therefore less important for treatment whether the tumor is adenocarcinoma or squamous cell carcinoma. It is much more important how far a non-small cell lung carcinoma has already spread in the body.
The three main therapeutic approaches are:
- Surgery, to surgically remove the tumor
- Radiation therapy to kill the cancer cells
- Chemotherapy with drugs that inhibit cell division
The exact therapeutic procedures for NSCLC are very complicated. Therefore, only a simplified overview can be given here.
Treatment in early and middle stages
If a non-small cell lung cancer is still relatively small, one tries to cut it out as completely as possible. To do this, the tumor should not have affected any or only a few lymph nodes and, above all, should not have metastasized.
In very early stages, surgery alone is often sufficient to remove the cancerous tissue completely. Sometimes the affected lung area is additionally irradiated. This kills any cancer cells that may have remained.
If non-small cell lung cancer has already spread and affected several lymph nodes, patients also receive chemotherapy (adjuvant chemotherapy) after surgery. For larger tumors, chemotherapy is sometimes started before surgery (neoadjuvant chemotherapy): It is intended to shrink the cancerous tumor. Then the surgeon has to cut out less tissue afterwards.
Treatment in advanced stages
Modern therapies for selected patients
In certain cases of non-small cell lung cancer, other therapeutic options may be considered. These include targeted therapies (with antibodies or tyrosine kinase inhibitors) and immunotherapies:
Targeted therapies specifically target certain features or characteristics of cancer cells. In non-small cell lung cancer, such targeted therapies may include antibodies or tyrosine kinase inhibitors.
- Antibody therapy involves administering man-made antibodies that target specific characteristics of non-small cell lung cancer. For example, some of these antibodies can destroy certain features on the surface of a cancer cell or the entire cancer cell.
- The tyrosine kinase inhibitors (tyrosine kinase inhibitors), which are also artificially produced, are taken up in the body by the cancer cells or by the cells of the blood vessel walls: Inside the cancer cells, they block signaling pathways that are important for tumor growth. Inside the vascular cells, they also block certain signaling pathways. As a result, the vessels cannot continue to grow or even perish. This impairs the tumor’s blood supply – its growth is slowed down.
However, some cancer tumors cause these checkpoints to cause the immune cells to also ignore and not attack the cancer cells. Affected patients may benefit from checkpoint inhibitors. These immunotherapeutic drugs ensure that immune checkpoints continue to function properly and increase their attack on cancer cells.
Both targeted therapies and immunotherapies can only be considered for patients in whom the tumor meets certain requirements (such as having a certain gene mutation or having certain docking sites on the surface). They are therefore only suitable for selected patients.
NSCLC: course and prognosis
Non-small cell lung cancer grows more slowly than small cell lung cancer. Therefore, in principle, it has a better prognosis. However, the chances of cure and life expectancy depend in individual cases on how early the tumor is detected and treated.
Other factors that influence how well non-small cell lung cancer can be treated include the patient’s general state of health and possible concomitant diseases such as high blood pressure or heart disease.
You can read more about the chances of cure and life expectancy of bronchial carcinoma in the text Lung cancer: Life expectancy.
