In Western industrialized countries, the number of lung cancer cases has been rising for years. Although the trend has been downward for men since the 1980s, women are showing new sad record numbers every year. Lung cancer is now the third most common form of cancer in both sexes. In Germany, more than 50,000 people are diagnosed with lung cancer every year. Even more alarming is its proportion of deaths: In men, lung cancer is the most common cause of cancer death, while in women it is still the third most common.
Smoking as a risk factor
These figures are all the more tragic because lung cancer is one of the few malignant tumors for which the main risk factor has been known for a long time: around 90 percent of lung cancer sufferers are smokers. If one considers that, according to one study, one in three 15-year-olds now smokes, with Germany among the sad leaders in an international comparison, it is highly likely that the number of lung cancer patients will not decrease in the future.
What is lung cancer?
Strictly speaking, lung cancer is a generic term for various malignant tumor diseases in the lungs and bronchial system. By far the most common form (90 percent) is bronchial carcinoma, which is often colloquially equated with lung cancer and is discussed here below. Metastases, i.e. daughter tumors of other types of cancer, can be washed into the lungs via the blood and settle there. Malignant tumors of the lung and pleura are rare. Depending on how the tissue appears under the microscope, small cell (25 percent) and non-small cell bronchial carcinoma are distinguished. The latter is further subdivided into different forms, including squamous cell carcinoma, which originates from the covering tissue and is the most common at about 45 percent, and adenocarcinoma, which, unlike all other forms, is not dependent on smoking. Small cell bronchial carcinoma spreads daughter tumors very early and therefore has a worse prognosis. In addition to the microscopic findings of the cell tissue, the tumor stage is also important for prognosis and therapy, i.e., how large the cancer is and how far it has already spread to surrounding structures and in the body at the time of diagnosis.
What are the causes of lung cancer?
Bronchial carcinoma develops primarily as a result of tobacco smoking. There are about 4,000 substances in cigarette smoke, 40 of which are carcinogenic, as well as benzo(a)pyrene, which damages a gene P-53 on chromosome 9 that is responsible for cancer defense. But not only active smoking is unhealthy; passive smoking also increases the risk of cancer. If a non-smoker spends a pleasant evening surrounded by smokers in a closed room, e.g. a pub, the body is exposed as if it had smoked 4 to 9 cigarettes. The risk of disease increases with the number of cigarettes, depth of inhalation, duration of smoking and age. Tar and nicotine concentrations also play a role. It is estimated that at 40 pack-years (i.e., one pack of cigarettes a day for 40 years), the risk of cancer is increased 30-fold. There is one piece of good news, however: if smokers manage to kick their nicotine habit, the likelihood of developing lung cancer gradually approaches that of nonsmokers again.
Toxins in the air as a cause of lung cancer
In addition to smoking, other toxins in the air you breathe can also cause lung cancer, especially if you are exposed to them for a long time. These include asbestos, arsenic, chromium, cadmium, nickel, polycyclic aromatic hydrocarbons, mustard gas, uranium, radon, and others.For example, blast furnace workers, gas plant workers, roofers, and asphalt cooks are at risk, especially if they disregard occupational safety regulations. The combination of these pollutants with active smoking is particularly dangerous. However, why some smokers develop cancer while others are spared despite decades of nicotine addiction has not yet been clarified. A clear hereditary cause has not yet been found, nor has a diet-related cause. However, scientists assume that there are connections.
Lung cancer: symptoms and signs
How does lung cancer manifest itself? It is treacherous that lung cancer usually does not cause any symptoms for a very long time. Therefore, lung cancer is often discovered either by chance during an X-ray examination or only when it is already advanced and accordingly poorly curable.In contrast to some other types of cancer, there is currently also no preventive examination offered that would be suitable as screening for early detection. When symptoms do occur, they are usually indistinguishable from other lung diseases, at least initially. The following symptoms should prompt a visit to the doctor, especially if they occur in combination or over a long period of time:
- New onset, worsening or changing chronic irritable cough.
- Hemoptysis
- Difficulty breathing until shortness of breath
- Lung sounds when breathing, chest pain.
- Lung diseases such as bronchitis that do not heal
- Hoarseness, difficulty swallowing
- Fever, night sweats
- Fatigue, performance kink
- Loss of appetite, unwanted weight loss.
Other symptoms can occur when lung cancer spreads and metastases settle in other organs. The spine, brain, adrenal glands and liver are particularly commonly affected, which can lead to back pain, headaches, dizziness, behavioral changes, abdominal pain or nausea.
How is the diagnosis made?
By means of the examinations, not only the tumor is found, but also its type and stage are determined in order to decide on the treatment. First, the doctor will ask the medical history, especially including smoking habits and occupational risk. The physical examination will be followed by X-rays of the lungs and various blood tests. In order to assess the tumor tissue, a lung endoscopy may be performed, during which cell and tissue samples may also be taken. Computer tomography of the chest, upper abdomen and brain can be used to determine the extent of the cancer and to detect daughter tumors. A skeletal scintigraphy can be used to specifically search for metastases in the bone, followed by a bone marrow biopsy if necessary. In addition, a number of other examinations exist that are used depending on the case and before a planned operation.
What therapy is available?
Treatment depends on the type and spread of the tumor. As far as possible, an attempt is made to achieve a cure. However, this is only successful if all tumor tissue, including metastases and affected lymph nodes, can be removed. Only then can a recurrence be prevented. Depending on the type of cancer, stage and condition of the patient, surgery, chemotherapy, radiation therapy or a combination of these are used.
- Surgery: the right and left lungs consist of three and two lobes, respectively, made up of a total of ten and nine lung segments. Depending on the size of the tumor, a segment (partial lung resection) or a lobe (lobectomy) is removed, and more rarely the entire left or right lung (pneumectomy). A lung function test is performed beforehand to determine whether the remaining breathing activity is sufficient. Non-small cell forms are particularly suitable for surgery.
- Chemotherapy: cytostatics are usually given in several cycles, cell poisons that attack mainly cancer cells, but also do not spare the body’s own healthy cells. This is why there are often severe side effects. Especially small cell carcinoma respond to it.
- Radiotherapy: cells are damaged by X-rays in certain doses. Particularly small-cell lung cancer can be reduced thereby, one irradiates the skull, can possibly prevent a settlement of metastases.
Recently, scientists have found some new approaches at the molecular biological level, in which the cancer cells are targeted during therapy. Initial research results give hope that this will open up new treatment options for lung cancer in the future.
What is the course and prognosis?
Overall, lung cancer currently tends to be one of the most prognostically unfavorable cancers – 5 years after diagnosis, on average, only 13 to 14 percent of patients are still alive. However, prognosis depends strongly on the type, size, and spread of the tumor and thus responsiveness to therapy, as well as on the patient’s age and general condition. Early-stage squamous cell carcinoma has the relatively best prognosis, while small cell bronchial carcinoma has the worst. Untreated, it even leads to death within a few weeks.After completion of treatment, regular check-ups are important so that a recurring tumor can also be detected and treated at an early stage. And in any case, the affected person should consistently abstain from cigarettes.
