Lung cancer – symptoms and treatment
Definition of illness. Causes of the disease
Lung cancer is a malignant neoplasm of the respiratory system arising from the bronchial epithelium that lines the airways of the lower respiratory system.
Because the source of tumor formation is the epithelium of the bronchi changed due to various reasons, often in the scientific literature, you can find a different name for this disease – bronchogenic cancer or bronchogenic carcinoma.
Among malignant neoplasms, lung cancer occupies a leading position in the world regarding its incidence and mortality. For more than 30 years, it has been the main “oncological killer.” Men get sick six times more often than women. Over the past 20 years, the overall incidence has more than doubled, with 51% among men and 75% among women. 
The average age at which lung cancer is diagnosed is 71 years. The disease is most rarely found in people under 20 years of age. 
The causes or etiology of the disease can be divided into two main groups of factors:
- genetic – repeated cases of the disease in the family (three or more) and the primary assortment of tumors (two or more independent oncological diseases in one patient);
- Modifying – conditions that predispose or even provoke the occurrence of a tumor.
Modifying factors are divided into:
- exogenous (external) – smoking, air pollution with carcinogens (exhaust gases, radon), occupational hazards (asbestos), ionizing radiation;
- Endogenous (internal) – chronic diseases of the respiratory system (for example, tuberculosis and chronic obstructive pulmonary disease ), age over 45 years.   
Smoking is a leading risk factor.
One of the controllable exogenous modifying factors is tobacco smoking. The risk of developing lung cancer in a smoker depends on the number of cigarettes consumed daily, the duration of the act of smoking, the length of the smoker, and the type of cigarettes.  The cumulative risk of death from lung cancer in men who smoke is 22% (in women, 12%) higher than in non-smokers.
The risk of dying from lung cancer is 30% higher in women living with men who smoke.
Smoking cigars or pipes doubles the risk of developing lung cancer. 
Causes of lung cancer in non-smokers
Approximately 15% of lung cancer patients have never smoked or rarely smoked.  The exact cause of the development of the disease in them is unknown; ita genetic predisposition probably causes it in combination with the risk factors listed above.
Symptoms of lung cancer
Lung cancer has no specific symptoms; in 15% of cases, the disease is asymptomatic.
The first signs of lung cancer
The first symptoms of lung cancer include shortness of breath and cough, sometimes with bloody sputum.
All symptom complexes in bronchogenic cancer can be divided into three groups:
- pulmonary syndrome – symptoms associated with the intrathoracic spread of the tumor;
- extrapulmonary syndrome – symptoms associated with the extrathoracic spread of the tumor;
- Paraneoplastic syndromes are indirect signs that indicate the presence of a malignant tumor in the body.
Various complaints come to the fore depending on the clinical form of cancer. So, with central cancer, 80-90% of patients have a cough, which is often no longer perceived by the smoker as a signal of trouble. Half of the patients have hemoptysis, which also, unfortunately, does not always make them seek help.
Cough and blood in lung cancer:
An increase in body temperature and shortness of breath in central cancer is associated with impaired ventilation of a part or the entire lung and the development of an inflammatory process in it, which is caused by a tumor growing inside the lumen of the bronchus. That is why pneumonia that recurs twice a year should prompt the general practitioner, pulmonologist, and patient to a deep examination for the possible development of central lung cancer. 
Symptoms of peripheral lung cancer
Much more insidious is the peripheral form of lung cancer. Since the lung parenchyma does not contain pain receptors and the tumor node is located far from the large bronchi, its growth is asymptomatic for a long time. When the pleura is involved in the process (the membrane of the lung and chest cavity) or intrathoracic lymph nodes are affected by metastases, 60-65% of patients experience chest pain of varying severity, cough, shortness of breath in 30-40% of cases, and with the collapse of the tumor – clinical a picture of a lung abscess, sometimes hoarseness of voice.
Pancoast tumor symptoms
Pancoast cancer (a tumor of the superior sulcus of the lung) is characterized by a special triad of symptoms (Bernard-Horner syndrome):
- drooping of the upper eyelid;
- constriction of the pupil on the side of the lesion;
- retraction of the eyeball. 
Also, this type of cancer can grow into the pleura, brachial plexus, or ribs, and therefore, on the side of the lesion, pain in the shoulder and arm as a whole, weakness, and atrophy of the hand may occur. 
Syndrome of hormonal disorders
There is no direct relationship between lung cancer and the development of any endocrine pathology. However, lung cancer can lead to the decompensation of an already existing or latent endocrine disorder. There is a separate group of neuroendocrine tumors (most often, these are carcinoids), which are also found in the lung. Their symptoms are associated with hormonal disorders, such as Cushing’s syndrome, which elevated corticosteroid levels . This leads to excess fat in the upper back, muscle weakness, skin deterioration, increased blood pressure, and fatigue .
The pathogenesis of lung cancer
To understand the mechanism of the development of lung cancer, you need to know the structure of the bronchopulmonary system.
The lungs have a tree-like structure; the bronchi are the branches, and the lung tissue (parenchyma) is the crown. This is where the term “bronchial tree” comes from.
Like a tree trunk, the trachea (central breathing tube) divides into two bronchi: right and left. Depending on the number of lobes in the lung, the main bronchi break up into two (left) and three (right) lobar bronchi. The lobar bronchi give rise to a corresponding number of bronchial tubes to the lung segments (each lung has ten such tubes). This division occurs up to level 22, where the lungs end with the formation of terminal and alveolar bronchioles, in which gas exchange occurs.
Prolonged exposure to risk factors on the ciliated epithelium of the bronchi leads to disruption of the protective mechanisms for the formation and excretion of sputum and, consequently, to the direct effect of carcinogens on the tissues of the respiratory tract.
The second line of defense against the adverse effects of carcinogens is the desquamation (exfoliation) of the damaged epithelium. Chronic damage to the respiratory epithelium causes pathological tissue regeneration and ultimately leads to the degeneration of the epithelium into bronchogenic carcinoma. 
Suppose the neoplasm develops in the large bronchi (up to the segmental level). In that case, the cancer is called central if the tumor has grown from the epithelium of a smaller bronchus – peripheral. This anatomical principle underlies the main approaches to diagnosing and treating various forms of lung cancer.
Classification and stages of development of lung cancer
Central lung cancer develops inside a large bronchus (endobronchial form) or around a bronchus (peribronchial-nodular and peribronchial-branched forms).
Peripheral lung cancer develops in the bronchi of a small caliber and most often represents a neoplasm (node) in the lung parenchyma. If such a node develops at the top of the lung and is accompanied by specific symptoms (Bernard-Horner syndrome), then such a tumor is called Pancoast cancer.
A rarer form of lung cancer is pneumonia-like. In this case, the tumor does not have one node but is scattered throughout the lung, resembling pneumonia on an x-ray. 
At the cellular level, the disease is divided into two types:
- small cell lung cancer: a neuroendocrine tumor;
- non-small cell lung cancer: squamous cell, adenocarcinoma, large cell, and other forms.
Squamous cell lung cancer is characterized by slow growth and a late tendency to metastasize. Small cell carcinoma has more rapid growth and is characterized by frequent hematogenous-lymphogenic metastasis in the early stages.
Stages of lung cancer
There are four stages of development in lung cancer and other malignant processes. In each stage of bronchogenic cancer, except for IV, substages “a” and “b” are distinguished.
- I, II, and IIIa stages of lung cancer are characterized by intrathoracic progression of the tumor,
- IIIb and IV stages of lung cancer – the release of tumor metastases outside the chest.
The stage IV of the process is determined by the formula TNM, where T is the prevalence of the maternal tumor, N is the presence of metastases in the lymph nodes closest to the maternal tumor, and M is the presence of distant metastases in other organs.
Such a complex multilevel classification is explained by the differences in the treatment tactics used for each specific clinical case of lung neoplasms.
Complications of lung cancer
The most formidable complication of lung cancer is pulmonary hemorrhage.
Not life-threatening, but no less serious complications of bronchogenic cancer are precancerous obstructive pneumonia and pleurisy.
Metastases in lung cancer
Complications of the metastatic process in lung cancer are:
- tumor stenosis (narrowing) of the trachea with the development of shortness of breath up to a severe form of respiratory failure;
- Dysphagia and broncho-esophageal fistulas (impaired swallowing and passage of the food coma into the stomach when the tumor invades the esophagus):
- Syndrome of compression of the superior vena cava (the main vessel that carries venous blood from the head and hands to the heart).
The favorite localization of metastases of small cell lung cancer is the brain, so the disease often manifests itself with neurological symptoms. In this case, the patient is urgently admitted to the neurosurgical department with a clinical picture of a stroke.
Most patients with stage III-IV lung cancer significantly decrease body weight. This is because a growing tumor and its metastases consume the protein-energy resource of the body while releasing the products of its vital activity, tumor toxins, into the blood. Oncologists call the extreme degree of exhaustion cancer cachexia.
The phase of upcoming complications often indicates that the disease is in the phase of full “bloom.” This sharply worsens not only life prognosis but, in many cases, makes it difficult and sometimes eliminates the possibility of using “aggressive” antitumor treatment.
Diagnosis of lung cancer
Our country has no screening (preventive) program for examining persons at risk for lung cancer.
X-ray diagnostic methods
Asymptomatic tumors of the respiratory organs in 85-90% of cases are detected by chance during fluorography, and therefore radiological methods for diagnosing bronchogenic cancer today occupy a leading place.  Among them are polypositional chest radiography, multislice computed tomography, and positron emission tomography.
What does a cancerous lung look like?
Histological and cytological techniques for examining lung cancer
When the clinical form of cancer (central or peripheral) is established, it is necessary to understand what histological structure (small cell or non-small cell) it is and to find out at what stage of development the detected tumor process is. The tactics of patient management chosen by the oncological council will depend on these three parameters.
To verify the histological form of cancer, invasive diagnostic methods come to the rescue:
- endoscopic (fibrobronchoscopy);
- Transthoracic (biopsy through an incision or puncture of the chest wall).
Only a comprehensive, system-by-system examination of the patient, including the digestive, reproductive, urinary, and other systems, helps to correctly establish the stage of the tumor process. Such a thorough approach to diagnosis takes some time, which often causes bewilderment and a lot of questions in a patient stunned by the diagnosis, and sometimes a false sense of delay in treatment. However, lung cancer is a chronic disease, and it is possible to be late only with the diagnosis of an early stage of tumor development.
Tumor markers in lung cancer
Tumor markers (CEA, NSE, CYFRA21-1) do not detect lung cancer at an early stage. Their noticeable increase indicates an already launched oncological process.
Lung Cancer Treatment
“Over the past 30 years, we have learned well only to classify lung cancer, but not to treat it,” one of the oncologists once said bitterly, half in jest, during a scientific and practical conference. This phrase is most clearly illustrated by the scene of the discharge from the oncological dispensary of one of the heroes of Alexander Solzhenitsyn’s novel “The Cancer Ward”:
Proshka walked merrily, and his white teeth sparkled. So, when it was necessary, they saw off and to freedom.
So what is written there? Proshka asked nonchalantly, taking the certificate.
“D-hell knows,” Kostoglotov twisted his mouth.
– Such cunning doctors have become, you will not read.
Proshka shook hands with all of them and, even from the stairs, turning around cheerfully, waved. And confidently descended to death.
And in the certificate for the medical institution at the residence was written: “Tumor pulmonum cum invasium cordis, casus inoperabilis ( Lung cancer, germinating in the heart, inoperable case ).” 
Indeed, statistics show that lung cancer, despite the ultra-modern diagnostic equipment in the leading countries of the world, is diagnosed in more than 80% of cases at an inoperable stage, i.e., when it is either impossible to surgically remove the tumor or its removal will not solve the patient’s problem and will not improve his long-term prognosis. At the same time, the surgical method of treating lung cancer today remains the patient’s only hope for a complete cure. 
A radically performed operation at stages I-II, supported by chemoradiotherapy according to indications, allows patients to survive the 5-year milestone and return to their usual full life. 
Radiation therapy for lung cancer
Radiation therapy is a method of local impact on the tumor and metastasis zones. It is used in inoperable cases or to improve the effectiveness of surgical treatment. The total dose of radiation is divided into daily portions. Treatment continues until the patient receives the full calculated dose of radiation.
Chemotherapy for lung cancer
Chemotherapy differs from surgical and radiation treatments in that it affects not only the tumor and its metastases but also the entire body, killing all dividing cells, both tumor and healthy.
Chemotherapy is given both before and after surgery. It is prescribed alone or in combination with radiation therapy in inoperable cases. The duration of treatment depends on many factors: efficacy, tolerability, the severity of concomitant pathology, etc. It is impossible to name the most effective chemotherapy regimens for lung cancer since the effectiveness of treatment often depends on the individual properties of the tumor.
Targeted therapy for lung cancer
As for stages III and IV of bronchogenic cancer, in these cases, the main forces of oncologists are aimed at chronicizing the process and prolonging the patient’s life, which is achieved through chemoradiation but also targeted therapy.  Targeted drugs are modern medicines aimed only at a tumor (eng. target – goal). Interacting at the molecular level with the receptors of the mutated cancer cell, the targeted drug causes the tumor to stop growing and multiplying, which leads to its aging and death.
However, this treatment is possible only in patients with a gene mutation in tumor cells proven by a molecular genetic study.  You also need to understand that targeted therapy does not cure the patient; it is designed to improve the quality of life and increase its duration.
Symptomatic and palliative therapy of lung cancer
Any therapy used for inoperable forms of lung cancer can be called palliative, that is, aimed at temporarily improving the general condition by reducing the intensity of the symptoms of the disease. This includes radiation and chemotherapy.
Symptomatic therapy is also a palliative treatment method, but it is aimed only at improving the patient’s quality of life by eliminating or reducing the intensity of symptoms.
Palliative therapy can be carried out in an oncological hospital, and symptomatic therapy, as a rule, is used at home in the terminal phase of the disease under the dynamic supervision of a local oncologist or therapist. This type of therapy includes, for example, taking painkillers.
Folk methods of treatment
Traditional methods of treating lung cancer are useless at best and dangerous to health at worst. The sooner the patient turns to an oncologist and undergoes treatment, the higher his chances of survival.
The mortality rate for lung cancer has remained high for many years, so the survival prognosis is relatively low and stable. The life expectancy of a patient with lung cancer depends on an alliance of many factors, such as clinical and histological forms, the process stage, the timeliness of contacting an oncologist, the presence of comorbidities, and the volume of specialized care provided. 
According to statistics, lung cancer most often develops in the upper (40%) and lower (30%) lobes, least often in the middle (10%). In most cases, the tumor is formed in the large bronchi (80%).
It is generally accepted that central cancer progresses faster than peripheral cancer, causing several adverse symptoms in the early stages. As a rule, the life expectancy of patients with this type of tumor in advanced stages does not exceed four years.
Peripheral forms of lung cancer are less aggressive and exist for a long time without clinical manifestations.
The prognosis of the disease also depends on the histological structure of the tumor:
- Non-small cell lung cancer is formed in 80-85%, survival prognosis depends on the stage of the disease, but in general, it is relatively favorable.
- Small cell lung cancer is registered in 10-15% of cases, is a rather aggressive form of the tumor, is susceptible to chemotherapy, and undergoes regression in 60-80%.  mortality from this type of lung cancer is high: no more than 40% of patients can survive for five years at stages I-II of the neoplasm, two-year survival is 50%, and five-year survival is 10-15%.
Risk of relapse
The disease’s recurrence is called the tumor’s growth in the same localization where it was removed surgically or eliminated by other methods. Relapses of lung cancer are much less common than the progression of the disease.
Progression refers to the growth of metastases outside the area of the maternal tumor. Metastases are the “children” of the primary tumor, which have settled throughout the body even before the start of treatment but are invisible even to the most high-tech diagnostic methods. For this reason, an oncologist observes patients for five, and often more, years after the end of treatment. The more time has passed since the completion of therapy, the less likely the recurrence or progression of cancer is. Survival of patients with lung cancer is directly proportional to the stage of the disease: 88% of patients diagnosed at stage I and 19% of patients diagnosed at stage IV survived within one year .
Is it possible to reduce the risk of disease?
In the prevention of malignant lesions of the respiratory organs, the fight against both active and passive tobacco smoking, and the promotion of a healthy lifestyle, including the prevention of chronic diseases of the bronchopulmonary system, are at the forefront.
The International Agency for Research on Cancer claims that proper and timely prevention can halve the incidence of lung cancer.
The basis of primary prevention is made up of measures that are focused on eliminating external negative factors. Special state programs aim to combat air pollution and improve working conditions at hazardous production enterprises.
Important primary preventive measures:
- promotion of healthy lifestyles;
- restriction of places for smoking;
- warning labels on cigarettes;
- reduction in the volume of production of tobacco products;
- Increase in the cost of cigarettes.
Quitting smoking significantly reduces the likelihood of developing lung cancer, and the respiratory organs are gradually restored and cleared of harmful substances.
Secondary preventive measures aim to conduct routine medical examinations of people of various age categories. Computed tomography examines people at risk with tumors that can be detected early.
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