Lung cancer is a malignant tumor originating from the tissues of the bronchi or pulmonary parenchyma. Symptoms can be subfebrility, cough with sputum or streaks of blood, shortness of breath, chest pain, weight loss. Pleurisy, pericarditis, superior vena cava syndrome, pulmonary bleeding may develop. Accurate diagnosis requires radiography and CT of the lungs, bronchoscopy, sputum and pleural exudate examination, tumor or lymph node biopsy. Radical methods of treating include resection interventions in the volume dictated by the prevalence of the tumor, in combination with chemotherapy and radiation therapy.
ICD 10
C34 Malignant neoplasm of the bronchi and lung
Meaning
Lung cancer is a malignant neoplasm of epithelial origin that develops from the mucous membranes of the bronchial tree, bronchial glands (bronchogenic cancer) or alveolar tissue (pulmonary or pneumogenic cancer). Disease leads in the structure of mortality from malignant tumors. Mortality in disease is 85% of the total number of cases, despite the successes of modern medicine.
The development of lung cancer varies with tumors of different histological structure. Differentiated squamous cell carcinoma is characterized by a slow course, undifferentiated cancer develops rapidly and gives extensive metastases. Small cell lung cancer has the most malignant course: it develops covertly and quickly, metastasizes early, has a poor prognosis. Most often, the tumor occurs in the right lung – in 52%, in the left lung – in 48% of cases.
Causes of lung cancer
The factors of occurrence and mechanisms of disease development do not differ from the etiology and pathogenesis of other malignant lung tumors. Exogenous factors play a major role in the development of lung cancer:
- smoking
- pollution of the air basin with carcinogenic substances
- exposure to radiation (especially radon).
Pathogenesis
The cancerous tumor is mainly localized in the upper lobe of the lung (60%), less often in the lower or middle lobe (30% and 10%, respectively). This is due to the more powerful air exchange in the upper lobes, as well as the features of the anatomical structure of the bronchial tree, in which the main bronchus of the right lung directly continues the trachea, and the left one forms an acute angle with the trachea in the bifurcation zone. Therefore, carcinogenic substances, foreign bodies, smoke particles, rushing into well-aerated zones and lingering in them for a long time, cause the growth of tumors.
Metastasis is possible in three ways: lymphogenic, hematogenic and implantation. The most frequent is lymphogenic metastasis into bronchopulmonary, pulmonal, paratracheal, tracheobronchial, bifurcation, and esophageal lymph nodes. The first to be affected by lymphogenic metastasis are the pulmonal lymph nodes in the zone of division of the lobar bronchus into segmental branches. Then bronchopulmonary lymph nodes along the lobar bronchus are involved in the metastatic process.
In the future, metastases occur in the lymph nodes of the lung root and the unpaired vein, tracheobronchial lymph nodes. The following are involved in the process of pericardial, paratracheal and perinesophageal lymph nodes. Distant metastases occur in the lymph nodes of the liver, mediastinum, supraclavicular region. Metastasis of lung cancer by hematogenic path occurs when the tumor grows into the blood vessels, while the other lung, kidneys, liver, adrenal glands, brain, spine are most often affected. Implantation metastasis is possible along the pleura in case of tumor germination into it.
Classification
According to the histological structure, there are 4 types of disease: squamous, large-cell, small-cell and glandular (adenocarcinoma). Knowledge of the histological form of lung cancer is important in terms of the choice of treatment and prognosis of the disease. It is known that squamous cell lung cancer develops relatively slowly and usually does not give early metastases. Adenocarcinoma is also characterized by relatively slow development, but it is characterized by early hematogenous dissemination. Small cell and other undifferentiated forms are transient, with early extensive lymphogenic and hematogenous metastasis. It is noted that the lower the degree of differentiation of the tumor, the more malignant its course.
By localization relative to the bronchi, lung cancer may be:
- central, arising in large bronchi (main, lobar, segmental)
- peripheral, originating from the subsegmental bronchi and their branches, as well as from the alveolar tissue.
Central form is more common (in 70%), peripheral form is much less common (in 30%). The form of central lung cancer is endobronchial, peribronchial nodular and peribronchial branched. Peripheral cancer can develop in the form of a “spherical” cancer (round tumor), pneumonia-like cancer, cancer of the apex of the lung (Pancost). The classification of lung cancer according to the TNM system and the stages of the process is given in detail in the article “malignant lung tumors”.
Symptoms of lung cancer
The lung cancer clinic is similar to the manifestations of other malignant lung tumors. Typical symptoms are a persistent cough with mucopurulent sputum, shortness of breath, subfebrile body temperature, chest pain, hemoptysis. Some differences in the lung cancer clinic are due to the anatomical localization of the tumor.
Central lung cancer
A cancerous tumor localized in a large bronchus gives early clinical symptoms due to irritation of the bronchial mucosa, violation of its patency and ventilation of the corresponding segment, lobe or whole lung.
The involvement of the pleura and nerve trunks causes the appearance of pain syndrome, cancerous pleurisy and disorders in the innervation zones of the corresponding nerves (diaphragmatic, vagus or recurrent). Metastasis of lung cancer to distant organs causes secondary symptoms from the affected organs.
The germination of a bronchial tumor causes the appearance of a cough with sputum and often with an admixture of blood. When hypoventilation occurs, and then atelectasis of the segment or lobe of the lung is joined by cancerous pneumonia, manifested by increased body temperature, the appearance of purulent sputum and shortness of breath. Cancerous pneumonia responds well to anti-inflammatory therapy, but recurs again. Cancerous pneumonia is often accompanied by hemorrhagic pleurisy.
Germination or compression of the vagus nerve by the tumor causes paralysis of the vocal muscles and is manifested by hoarseness of the voice. Damage to the diaphragmatic nerve leads to paralysis of the diaphragm. The germination of a cancerous tumor into the pericardium causes the appearance of pain in the heart, pericarditis. The involvement of the superior vena cava leads to a violation of venous and lymphatic outflow from the upper half of the trunk. The so-called superior vena cava syndrome is manifested by puffiness and puffiness of the face, hyperemia with a cyanotic tinge, swelling of the veins on the arms, neck, chest, shortness of breath, in severe cases – headache, visual disorders and impaired consciousness.
Peripheral lung cancer
Peripheral lung cancer in the early stages of its development is asymptomatic, because there are no pain receptors in the lung tissue. As the tumor node increases, the bronchi, pleura, and neighboring organs are involved in the process. Local symptoms of peripheral form include cough with sputum and streaks of blood, compression syndrome of the superior vena cava, hoarseness of voice. The growth of the tumor into the pleura is accompanied by cancerous pleurisy and compression of the lung by pleural effusion.
The development of lung cancer is accompanied by an increase in general symptoms: intoxication, shortness of breath, weakness, weight loss, and an increase in body temperature. In advanced forms of lung cancer, complications from organs affected by metastases, the collapse of the primary tumor, the phenomena of bronchial obstruction, atelectasis, profuse pulmonary bleeding are added. The causes of death in lung cancer are most often extensive metastases, cancerous pneumonia and pleurisy, cachexia (severe exhaustion of the body).
Diagnostics of lung cancer
Diagnosis of suspected lung cancer includes:
- blood and urinalysis;
- cytological studies of sputum, bronchial flushing, pleural exudate;
- assessment of physical data;
- lung x-ray in 2 projections, linear tomography, CT of the lungs;
- bronchoscopy (fibrobronchoscopy);
- pleural puncture (if there is an effusion);
- diagnostic thoracotomy;
- a precalescent biopsy of lymph nodes.
Treatment for lung cancer
Leading in the treatment of lung cancer are the surgical method in combination with radiation therapy and chemotherapy. If there are contraindications or ineffectiveness of these methods, palliative treatment is carried out, aimed at alleviating the condition of an incurably ill patient. Palliative methods of treatment include anesthesia, oxygen therapy, detoxification, palliative surgery: tracheostomy, gastrostomy, enterostomy, nephrostomy, etc.). In case of cancerous pneumonia, anti–inflammatory treatment is carried out, in case of cancerous pleurisy – pleurocentesis, in case of pulmonary bleeding – hemostatic therapy.
Forecast
The worst prognosis is statistically noted for untreated lung cancer: almost 90% of patients die 1-2 years after diagnosis. With non-combined surgical treatment of lung cancer, the five-year survival rate is about 30%. Treatment of lung cancer at stage I gives a five–year survival rate of 80%, at stage II – 45%, at stage III – 20%.
Independent radiation or chemotherapy gives a 10% five-year survival rate for patients with this disease; with combined treatment (surgical + chemotherapy + radiation therapy), the survival rate for the same period is 40%. Prognostically unfavorable metastasis of lung cancer to lymph nodes and distant organs.
Prevention
The issues of lung cancer prevention are relevant due to the high mortality rates of the population from this disease. The most important elements of lung cancer prevention are active sanitation, prevention of the development of inflammatory and destructive lung diseases, detection and treatment of benign lung tumors, smoking cessation, elimination of occupational hazards and daily exposure to carcinogenic factors. Passing fluorography at least once every 2 years makes it possible to detect lung cancer in the early stages and prevent the development of complications associated with advanced forms of the tumor process.
Literature
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