Small cell lung cancer is a malignant neoplasm, accounting for approximately 15% of all primary lung cancers. The main cause of its occurrence is cigarette smoking. Small cell lung cancer is aggressive and its first symptoms are nonspecific, which makes it very dangerous. How is the diagnosis and treatment of small cell lung cancer carried out? What is the prognosis for this cancer?

Small cell lung cancer , among other lung cancers, it is distinguished by relatively high aggressiveness, rapid growth and early metastasis to both nearby lymph nodes and distant organs.

Treatment of this form of cancer is difficult and the prognosis is usually serious, although it depends on the stage of the disease at diagnosis.

Learn about the symptoms of small cell lung cancer and the process of its diagnosis and treatment.

Small Cell Lung Carcinoma: Features

The most important risk factor for the development of small cell lung cancer is smoking - it is estimated that as many as 95% of cases of this cancer occur in smokers. This type of neoplasm is most often located near the central lungs, the place where the bronchi and vessels enter the lung parenchyma from the mediastinum (the parietal region).

Small cell lung cancer has a special microscopic structure - its cells have neuroendocrine abilities, which consist in producing and releasing various substances into the blood.

These are the most common proteins and hormones that cause the so-called paraneoplastic syndromes, i.e. symptoms that may constitute the first signs of cancer development in the body. Small cell carcinoma cells also have the ability to divide rapidly, resulting in aggressive tumor growth.

Usually, at the time of diagnosis, the neoplasm already spreads to the surrounding lymph nodes, and sometimes it also metastasizes in distant organs. Metastatic lesions typically locate in the liver, brain, and bones. Depending on the stage of the disease, there are 2 types of small cell carcinoma:

  • limited disease(LD variant), in which the tumor covers one lung andnearby lymph nodes
  • disseminated form of small cell lung cancer(ED variant - extensive disease), in which the tumor covers a larger area or forms distant metastases

This division plays an important role in the selection of a therapy regimen, as both variants differ in the treatment strategy. Therapy of small cell carcinoma rarely involves surgical (operative) treatment, as the rapid progression of the tumor to disseminated form makes its complete removal difficult.

This type of cancer is sensitive to both chemotherapy and radiation therapy. Unfortunately, despite this, the statistics on treatment effectiveness and survival are not optimistic.

About 15% of patients diagnosed with a limited form of small cell carcinoma survive 5 years, while the diagnosis of disseminated cancer is associated with a low chance of long-term survival.

Important

Lung cancer - check if you are at risk

  • Smoking - this is the main culprit (the cause of 90% of all cases), increases the risk of lung cancer 20 times.
  • Passive smoking - frequent exposure to smoking rooms increases the risk of getting sick three times.
  • Contact with a contaminated environment - breathing in polluted air, contact with toxic compounds, e.g. lead, beryllium, chromium, nickel, asbestos or generated during coal gasification.
  • Genetic burden - a family history of cancer.
  • Gender - Women who smoke the same number of cigarettes as men are at greater risk of lung cancer than men.

Small Cell Lung Carcinoma: Symptoms

Small cell carcinoma causes both local symptoms, related to infiltration of the bronchial walls and destruction of the lung parenchyma, and systemic ones, especially in the advanced stage of the disease.

Tumor development in the airways is usually manifested by persistent coughing, shortness of breath, and haemoptysis.

Cancer can also cause recurrent pneumonia.

Such symptoms, combined with general weakness, weight loss and a feeling of being unwell, should always prompt you to see a doctor.

Rapid growth of small cell carcinoma and infiltration of the mediastinal structures may cause the so-called superior vena cava syndrome. The growing tumor compresses the superior vena cava that runs there and blocks the blood flow.

This compression leads to stagnation of blood in the veins above the stenosis, which gives the characteristic symptoms localized in the upper parts of the body. These include redness and swelling of the face, widening of the veins in the neckand chest, mucous membranes and conjunctiva congestion, headaches and visual disturbances.

Another group of symptoms typical for small cell carcinoma are the so-called paraneoplastic (or paraneoplastic) syndromes, which are often the first symptom of the disease. The cause of these syndromes is the release of hormonal molecules by cancer cells that affect the functioning of the entire body. The most common are:

  • Lambert-Eaton myasthenic syndrome, consisting in weakening the strength of the muscles of the upper and lower extremities, easy fatigue and the abolition of neurological reflexes. Patients most often complain of muscle pain when lifting their arms or climbing stairs
  • syndrome of inappropriate antidiuretic hormone release (SIADH) in which mainly neurological symptoms such as headache, nausea and vomiting, confusion, and in severe forms seizures and coma
  • Cushing's syndrome, associated with the release of the adrenocorticotropic hormone ACTH. Its features include obesity with a special distribution of fat around the face, neck and abdomen, arterial hypertension, thinning of the skin with a tendency to stretch marks, muscle atrophy and visual disturbances
  • degeneration of the cerebellar cortex, manifested by nystagmus, disturbances in balance, motor coordination and speech.

It is significant that there are many types of paraneoplastic syndromes, depending on the type of substances produced by the cancer cells.

These diseases may affect tissues and organs distant from the primary tumor site - skin, vessels, bones and the central nervous system.

Suspicion or diagnosis of any of them should be an alarming signal for the patient and the doctor, prompting them to undertake in-depth oncological diagnostics.

Small cell lung cancer: diagnosis

The first examination ordered when lung cancer is suspected is usually a chest X-ray. They are performed to visualize both the tumor itself and the changes it causes in the lung image, such as the presence of fluid or atelectasis (lack of air in the alveoli).

It should be remembered, however, that the X-ray image is not very precise and not every tumor will be visible on it - it is especially difficult to visualize tumors in the mediastinal location.

Usually, if the disturbing symptoms persist and the X-ray does not change, additional imaging tests are performed.

For a more detailed evaluationComputed tomography of the chest is used for the parenchyma of the lungs, mediastinal structures and the surrounding lymph nodes.

In the case of lesions suspected of cancerous nature, a PET (Positron Emission Tomography) test is usually ordered. It enables the detection of both the primary tumor focus and the lymph nodes it has involved, as well as metastatic changes in other organs.

The diagnosis of small cell carcinoma is based on a histopathological examination, i.e. viewing tumor fragments under a microscope.

The typical location of the tumor in the central region of the chest causes that the most common method of collecting a tumor tissue specimen is bronchoscopy. It consists in inserting a special speculum into the bronchi, examining the respiratory tract with a camera installed in it and a biopsy, i.e. collecting a fragment of suspicious tissue with special forceps.

In rare cases where the tumor is located near the chest wall, the material for examination is obtained through the so-called a transthoracic biopsy, i.e. a puncture of this wall. Each of these procedures is performed under local anesthesia.

An additional test performed in the case of suspicion of lung cancer is a laboratory determination of the level of the so-called tumor markers. These are substances whose high blood levels may indicate the development of cancer. The most frequently marked markers are: CEA (carcinoembryonic antigen) and NSE (specific neuronal enolase), which is a typical marker of small cell carcinoma.

The initiation of small cell carcinoma therapy is always preceded by tumor staging assessment.

For this purpose, additional imaging tests are performed, primarily aimed at finding possible metastases. These include:

  • CT of the abdominal cavity and thorax with contrast
  • MR or CT of the brain
  • bone scintigraphy

If bone marrow involvement is suspected, a bone marrow biopsy is performed. On the basis of the above-mentioned The research determines the stage of cancer according to the TNM classification. This classification takes into account:

  • tumor size (T-tumor)
  • lymph node involvement (N-nodes)
  • presence of distant metastasis
Important

Lung cancer: types

  • Squamous cell carcinomais the most common, accounting for 40 percent of all primary lung cancers. In more than 90 percent of cases, it is a consequence of smoking. Relative to other lung tumors, it is first to show symptoms. It is more common in men, but recent years show thatthe proportions between men and women are equal.
  • Small cell carcinomaaccounts for approximately 20 percent of lung cancer cases. Its name comes from the size of the cells that form the tumor. They are smaller than the cells in the lung. It is dangerous because it develops in the peripheral parts of the lung, which causes symptoms late. The disease is believed to be strongly related to smoking. Small cell carcinoma is amenable to chemotherapy and radiotherapy, but is also characterized by a high number of relapses. Surgery is not performed in this cancer.
  • Adenocarcinomaaccounts for about 30 percent of lung cancers. It usually develops in the peripheral parts of the lung and therefore becomes symptomatic late. Its development is not directly related to smoking. Women get sick more often.
  • Large cell carcinoma- Affects 10-15 percent of cases. It has the features of a Euroendocrine tumor, which means that it may exhibit hormonal activity.

Small Cell Lung Carcinoma: Treatment

The choice of the type of therapy depends on the stage of the cancer at the time of diagnosis. About 30% of patients are diagnosed with the reduced form, which gives a much greater chance of responding to treatment.

The result of many years of research is the development of the most popular model of combined therapy, i.e. simultaneous chemotherapy and radiotherapy, the effectiveness of which is greater than the use of each of these methods separately.

The most commonly used chemotherapeutic agents are 4-6 cycles of cisplatin and etoposide.

Irradiation of the chest is performed simultaneously with the administration of chemotherapy. The standard radiation therapy schedule is 5 days a week for 6 weeks.

If the cancer responds to treatment and it is possible to inhibit its growth in the lungs, the next step is preventive brain radiation. This therapy reduces the risk of metastases within the central nervous system.

Some very early stage small cell carcinomas (when the tumor is small, limited and not yet showing any symptoms) are treated with surgery followed by standard chemotherapy.

The disseminated form of neoplasm is associated with a much worse prognosis and a low chance of long-term survival. As a standard, the detection of small cell carcinoma at the disseminated stage results in the introduction of chemotherapy in a scheme analogous to the one described above.

Obtaining a response to treatment also enables, in some cases, prophylactic brain radiation therapy. Chemotherapy is also usedin relapses - depending on whether the previously used drugs were effective, the same or a changed regimen is implemented.

Small cell cancer cure rates are still unsatisfactory - only 15-20% of patients diagnosed with the disease in a limited stage survive the next 5 years.

For this reason, intensive clinical research is being conducted into new methods of treatment.

It should be remembered that the most effective method of preventing small cell lung cancer is avoiding or quitting smoking - cigarettes cause up to 95% of cases of this cancer.

About the authorKrzysztof BialaziteA medical student at Collegium Medicum in Krakow, slowly entering the world of constant challenges of the doctor's work. She is particularly interested in gynecology and obstetrics, paediatrics and lifestyle medicine. A lover of foreign languages, travel and mountain hiking.

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Category:

Oncology